mk/genlink: change devices.data format to remove gcc specific options

As discussed with karlp on irc the devices.data file should not contain
gcc specific command line options.

For that reason the command line options for gcc are now generated from
the variables CPU and FPU by the rules in the mk directory.

This breaks the genlink tests.

genlink: simplified devices.data

devices.data already had the information about the family name.
By using the first field (by the pattern used to match it) as family name information that data doesn't
have to be provided explicitly. The same data is used to generate the
CPPFLAGS, such as -DSTM32F1

The architectures block of the devices.data file was redundant.

genlink-config.mk uses family and subfamily to figure out which libopencm3
variant actually exists.

mk/README

@@ -15,34 +15,31 @@ where you are defining variables (near the beginning of the file), and file
 <module>-rules.mk should be included in the rules part of makefile (somewhere
 near to the end of file).
 
-Example makefile using gcc compiler module:
+Example makefile using the gcc compiler module together with the linker script
+generator module:
 
 >>>>>>
-OBJS		+= foo.o bar.o
+DEVICE          =
+OPENCM3_DIR     =
+OBJS            += foo.o
 
-CFLAGS		+= -O0 -g
-CPPFLAGS	+= -MD -MP $(@F).d
-CPPFLAGS	+= $(DEFS)
-CPPFLAGS	+= $(INCS)
-LDFLAGS		+= --static --nostartfiles
-LDLIBS		+= -Wl,--start-group -lc -lgcc -lnosys -Wl,--end-group
-# parameters for gcc module
-PREFIX		= arm-elf
+CFLAGS          += -Os -ggdb3
+CPPFLAGS	+= -MD
+LDFLAGS         += -static -nostartfiles
+LDLIBS          += -Wl,--start-group -lc -lgcc -lnosys -Wl,--end-group
 
+include $(OPENCM3_DIR)/mk/genlink-config.mk
 include $(OPENCM3_DIR)/mk/gcc-config.mk
 
 .PHONY: clean all
 
-all: binary.images
-
-%.images: %.elf %.hex
-
-include $(OPENCM3_DIR)/mk/gcc-rules.mk
+all: binary.elf binary.hex
 
 clean:
-	$(Q)$(RM) -rf binary.* *.o *.d
+	$(Q)$(RM) -rf binary.* *.o
 
--include $(OBJS:.o=.d)
+include $(OPENCM3_DIR)/mk/genlink-rules.mk
+include $(OPENCM3_DIR)/mk/gcc-rules.mk
 <<<<<<
 
 
@@ -81,7 +78,8 @@ genlink
 
   This module adds an support for the user to the linker script generator. The
 linker script will be generated as the file $(DEVICE).ld in the project folder,
-and automatically used for the linking process.
+and automatically be used for the linking process.
+Additionally the matching library is added to the LDLIBS variable.
 
 Variables to control the build process (should be set in your makefile):
 ------------------------------------------------------------------------
@@ -92,9 +90,9 @@ OPENCM3_DIR	The root path of libopencm3 library.
 Output variables from this module:
 ----------------------------------
 
-DEFS		(appended)
- - Appended definitions specified in chip database file.
- ! Ensure that you have line 'CPPFLAGS += $(DEFS)' in your makefile.
+CPPFLAGS		(appended)
+ - Appends the chip family to the CPPFLAGS. For example -DSTM32F1
+ - Appends the include path for libopencm3
 
 ARCH_FLAGS	(replaced)
  - Architecture build flags for specified chip.
@@ -104,12 +102,16 @@ LDSCRIPT	(replaced)
  - Linker script generated file.
  * No needed to handle this variable if you use module <gcc> too.
 
-OPENCM3_LIBNAME	(replaced)
- - The right libopencm3 library base name to be linked with.
- ! Ensure that you have line 'LDLIBS += -l$(OPENCM3_LIBNAME)' in your makefile.
- ! Ensure that you have line 'LDFLAGS += -L$(OPENCM3_DIR)/lib' in your makefile.
- ! Ensure that you have rule '$(OPENCM3_DIR)/lib/lib$(OPENCM3_LIBNAME).a:'
-   to be the library archive successfully built when needed.
+LDLIBS (appended)
+ - LDLIBS += -lopencm3_$(family) is appended to link against the
+   matching library.
+
+LDFLAGS (appended)
+ - LDFLAGS += -L$(OPENCM3_DIR)/lib is appended to make sure the
+   matching library can be found.
+
+family,cpu,fpu (replaced)
+ - these are used internally to create the above variables
 
 Temporary variables that you should not use in your makefile:
 -------------------------------------------------------------