Synchronise linker scripts which are supposed to be identical

This also report bug fixes about data alignment and bss storage to EFM32 &
LM3S targets.

Note: removed chrysn copyright statement as the file is a verbatim copy of
previous files.

lib/lm3s/libopencm3_lm3s.ld

@@ -77,8 +77,6 @@ SECTIONS
 
 	. = ALIGN(4);
 	end = .;
-	_end = .;
-	__end = .;
 }
 
 PROVIDE(_stack = ORIGIN(ram) + LENGTH(ram));