serial: ns16550: fix comment to mention schedule instead of watchdog_reset

watchdog_reset() is no more. Make the comments match the code and
today's reality.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 4963385..42b6971 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -291,9 +291,9 @@
 	serial_out(c, &com_port->thr);
 
 	/*
-	 * Call watchdog_reset() upon newline. This is done here in putc
+	 * Call schedule() upon newline. This is done here in putc
 	 * since the environment code uses a single puts() to print the complete
-	 * environment upon "printenv". So we can't put this watchdog call
+	 * environment upon "printenv". So we can't put this schedule call
 	 * in puts().
 	 */
 	if (c == '\n')
@@ -390,9 +390,9 @@
 	serial_out(ch, &com_port->thr);
 
 	/*
-	 * Call watchdog_reset() upon newline. This is done here in putc
+	 * Call schedule() upon newline. This is done here in putc
 	 * since the environment code uses a single puts() to print the complete
-	 * environment upon "printenv". So we can't put this watchdog call
+	 * environment upon "printenv". So we can't put this schedule call
 	 * in puts().
 	 */
 	if (ch == '\n')