serial: kgdb_nmi: Use bool function return values of true/false not 1/0

Use the normal return values for bool functions
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/kgdb_nmi.c

@@ -173,18 +173,18 @@ static int kgdb_nmi_poll_one_knock(void)
 bool kgdb_nmi_poll_knock(void)
 {
 	if (kgdb_nmi_knock < 0)
-		return 1;
+		return true;
 
 	while (1) {
 		int ret;
 
 		ret = kgdb_nmi_poll_one_knock();
 		if (ret == NO_POLL_CHAR)
-			return 0;
+			return false;
 		else if (ret == 1)
 			break;
 	}
-	return 1;
+	return true;
 }
 
 /*