MIPS: Complete `status' to `err' renaming in `mips_breakpoint_from_pc'

MIPS: Complete `status' to `err' renaming in `mips_breakpoint_from_pc'

Complement commit d09f2c3f [target_read_memory&co: no longer return
target_xfer_status] and apply the same change made to the big-endian leg
of the function to the little-endian leg as well.

	gdb/
	* mips-tdep.c (mips_breakpoint_from_pc): Rename local `status'
	to `err' in the little-endian leg.