Rename SPL_WATCHDOG_SUPPORT to SPL_WATCHDOG

Rename this option so that CONFIG_IS_ENABLED can be used with it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/vining_2000_defconfig b/configs/vining_2000_defconfig
index 0108738..b908ca0 100644
--- a/configs/vining_2000_defconfig
+++ b/configs/vining_2000_defconfig
@@ -32,7 +32,7 @@
 CONFIG_SPL_USB_HOST_SUPPORT=y
 CONFIG_SPL_USB_GADGET=y
 CONFIG_SPL_USB_SDP_SUPPORT=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_BOOTZ=y
 CONFIG_CMD_GPIO=y