examples: Remove duplicate example linker scripts.

Only add one linker script per eval board, and have the Makefiles use that.

This avoids duplication, and various copy-paste errors and left-overs
which we already have in the tree.

Some of the linker scripts are not really correct, yet. Both, the comments
which say which board, chip, and RAM/ROM sizes are used, as well as the
actual RAM/ROM size definitions are sometimes copy-pasted from other boards
and are thus incorrect. This needs to be fixed.

examples/lm3s/Makefile.include

@@ -29,7 +29,7 @@ OBJDUMP		= $(PREFIX)-objdump
 TOOLCHAIN_DIR   = ../../../..
 CFLAGS		+= -O0 -g3 -Wall -Wextra -I$(TOOLCHAIN_DIR)/include -fno-common \
 		   -mcpu=cortex-m3 -mthumb -MD
-LDSCRIPT	= $(BINARY).ld
+LDSCRIPT	?= $(BINARY).ld
 LDFLAGS         += -L$(TOOLCHAIN_DIR)/lib -L$(TOOLCHAIN_DIR)/lib/lm3s \
 		   -T$(LDSCRIPT) -nostartfiles -Wl,--gc-sections
 OBJS		+= $(BINARY).o