MIPS16/opcodes: Keep the LSB of PC-relative offsets in disassembly

MIPS16/opcodes: Keep the LSB of PC-relative offsets in disassembly

Correct the disassembly of the PC-relative immediate argument of the
MIPS16 synthetic LA, LW, DLA and LD instructions and do not mask the
LSB, which in this case is a part of the data address rather than the
ISA bit and has to be fully presented.

	opcodes/
	* mips-dis.c (print_insn_arg): Only clear the ISA bit for jumps
	and branches and not synthetic data instructions.

	binutils/
	* testsuite/binutils-all/mips/mips16-undecoded.d: Adjust the
	disassembly of PC-relative LA and LW synthetic instructions.