* msp430/Makefile.in (CRT_OBJS): Add crt_high_bss.o.
	* msp430/crt0.S (high_bss): Add.
	* msp430/msp430-sim.ld: Add error message if .upper sections are
	detected.
	* msp430/msp430xl-sim.ld (MEMORY): Adjust to better mimic real
	life MCUs.  Add support for upper and lower sections.