powerpc/xmon: Use rtas_call_unlocked() in xmon

Avoid open coding the logic by using rtas_call_unlocked().
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/xmon/xmon.c

@@ -320,6 +320,7 @@ static inline void disable_surveillance(void)
 #ifdef CONFIG_PPC_PSERIES
 	/* Since this can't be a module, args should end up below 4GB. */
 	static struct rtas_args args;
+	int token;
 
 	/*
 	 * At this point we have got all the cpus we can into
@@ -328,17 +329,12 @@ static inline void disable_surveillance(void)
 	 * If we did try to take rtas.lock there would be a
 	 * real possibility of deadlock.
 	 */
-	args.token = rtas_token("set-indicator");
-	if (args.token == RTAS_UNKNOWN_SERVICE)
+	token = rtas_token("set-indicator");
+	if (token == RTAS_UNKNOWN_SERVICE)
 		return;
-	args.token = cpu_to_be32(args.token);
-	args.nargs = cpu_to_be32(3);
-	args.nret = cpu_to_be32(1);
-	args.rets = &args.args[3];
-	args.args[0] = cpu_to_be32(SURVEILLANCE_TOKEN);
-	args.args[1] = 0;
-	args.args[2] = 0;
-	enter_rtas(__pa(&args));
+
+	rtas_call_unlocked(&args, token, 3, 1, NULL, SURVEILLANCE_TOKEN, 0, 0);
+
 #endif /* CONFIG_PPC_PSERIES */
 }