arch/tile: avoid __must_check warning on one strict_strtol check

For the "initfree" boot argument it's not that big a deal, but
to avoid warnings in the code, we check for a valid value before
allowing the specified argument to override the kernel default.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

arch/tile/mm/init.c

@@ -988,8 +988,12 @@ static long __write_once initfree = 1;
 /* Select whether to free (1) or mark unusable (0) the __init pages. */
 static int __init set_initfree(char *str)
 {
-	strict_strtol(str, 0, &initfree);
-	pr_info("initfree: %s free init pages\n", initfree ? "will" : "won't");
+	long val;
+	if (strict_strtol(str, 0, &val)) {
+		initfree = val;
+		pr_info("initfree: %s free init pages\n",
+			initfree ? "will" : "won't");
+	}
 	return 1;
 }
 __setup("initfree=", set_initfree);