* remote-mips.c (mips_insert_breakpoint, mips_remove_breakpoint):

	* remote-mips.c (mips_insert_breakpoint, mips_remove_breakpoint):
	New functions.
	(mips_store_word): Change calling convention to return errors, and
	to provide old contents if the caller wants it.
	(mips_xfer_memory): Deal with errors from mips_store_word.
	* config/mips/tm-idt.h, config/mips/tm-idtl.h: Remove BREAKPOINT
	define now that remote-mips.c doesn't use BREAKPOINT.