Adds support for placing MSP430 code and data into either low memory or high memory.

Adds support for placing MSP430 code and data into either low memory or high memory.

	* msp430/msp430.ld: Delete.
	* msp430/msp430F5438A-l.ld: Delete.
	* msp430/msp430F5438A-s.ld: Delete.
	* msp430/crt_movedata.S: Delete.

	* msp430/Makefile.in (SCRIPTS): Remove msp430.ld.
	(CRT_OBJS): Add crt_move_highdata.o.
	* msp430/memmodel.h (START_CRT_FUNC): New macro.
	(END_CRT_FUNC): New macro.
	(WEAK_DEF): New macro.
	* msp430/crt0.S: Use new macros.
	(move_highdata): New code to initialise the .data section if it is
	held in high memory.

	* msp430/msp430-sim.ld (.data): Add .either.data.
	(.rodata2): Move some read-only data sections here.
	(.text): Add .either.text.
	(.rodata): Add .either.rodata.
	(.bss): Add .either.bss.
	* msp430/msp430xl-sim.ld (MEMORY): Add HIROM.
	(.rodata2): Move some read-only data sections here.
	(.upper.data): New section.  Include notes about how to initialise
	it.