MIPS: uasm: add wait instruction

This patch allows use of the wait instruction from uasm. It will be used
by a subsequent patch.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>

diff --cc arch/mips/include/asm/uasm.h
Simple merge

diff --cc arch/mips/mm/uasm-micromips.c
Simple merge

diff --cc arch/mips/mm/uasm-mips.c
Simple merge

diff --cc arch/mips/mm/uasm.c
Simple merge