core: Implement the wait instruction as a no-op

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

decode1.vhdl

@@ -364,6 +364,7 @@ architecture behaviour of decode1 is
         2#0000000100#  =>       (ALU,    OP_TRAP,      RA,         RB,          NONE, NONE, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '1', '0', NONE, '0', '1'), -- tw
         2#0100110010#  =>       (LDST,   OP_TLBIE,     NONE,       RB,          RS,   NONE, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '0'), -- tlbie
         2#0100010010#  =>       (LDST,   OP_TLBIE,     NONE,       RB,          RS,   NONE, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '0'), -- tlbiel
+        2#0000011110#  =>       (ALU,    OP_NOP,       NONE,       NONE,        NONE, NONE, '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', NONE, '0', '1'), -- wait
         2#0100111100#  =>       (ALU,    OP_XOR,       NONE,       RB,          RS,   RA,   '0', '0', '0', '0', ZERO, '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '0'), -- xor
         others => illegal_inst
 	);