target/openrisc: Always exit after mtspr npc

We have called cpu_restore_state asserting will_exit.
Do not go back on that promise.  This affects icount.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/openrisc/sys_helper.c

@@ -51,8 +51,8 @@ void HELPER(mtspr)(CPUOpenRISCState *env, target_ulong spr, target_ulong rb)
         if (env->pc != rb) {
             env->pc = rb;
             env->dflag = 0;
-            cpu_loop_exit(cs);
         }
+        cpu_loop_exit(cs);
         break;
 
     case TO_SPR(0, 17): /* SR */