or1k: add missing l.msync, l.psync and l.psync instructions.

Even though the opcodes were defined for these instructions,
the actual instruction definitions were lacking.

cpu/
	* or1korbis.cpu (l-msync, l-psync, l-csync): New instructions.

opcodes/
	* or1k-desc.c, * or1k-desc.h, * or1k-opc.c, * or1k-opc.h,
	* or1k-opinst.c: Regenerate.