cyclic: Use schedule() instead of WATCHDOG_RESET()

Globally replace all occurances of WATCHDOG_RESET() with schedule(),
which handles the HW_WATCHDOG functionality and the cyclic
infrastructure.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Tom Rini <trini@konsulko.com> [am335x_evm, mx6cuboxi, rpi_3,dra7xx_evm, pine64_plus, am65x_evm, j721e_evm]
diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
index 30650e3..0d43e9b 100644
--- a/drivers/serial/serial-uclass.c
+++ b/drivers/serial/serial-uclass.c
@@ -246,7 +246,7 @@
 	do {
 		err = ops->getc(dev);
 		if (err == -EAGAIN)
-			WATCHDOG_RESET();
+			schedule();
 	} while (err == -EAGAIN);
 
 	return err >= 0 ? err : 0;