MIPS: inst.h: define COP0 wait op

The func field for the wait instruction was missing from inst.h - this
patch adds it.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>

arch/mips/include/uapi/asm/inst.h

@@ -125,7 +125,8 @@ enum bcop_op {
 enum cop0_coi_func {
 	tlbr_op	      = 0x01, tlbwi_op	    = 0x02,
 	tlbwr_op      = 0x06, tlbp_op	    = 0x08,
-	rfe_op	      = 0x10, eret_op	    = 0x18
+	rfe_op	      = 0x10, eret_op	    = 0x18,
+	wait_op       = 0x20,
 };
 
 /*