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/mx6ul_14x14_evk_defconfig b/configs/mx6ul_14x14_evk_defconfig
index 26280fb..96d9abc 100644
--- a/configs/mx6ul_14x14_evk_defconfig
+++ b/configs/mx6ul_14x14_evk_defconfig
@@ -28,7 +28,7 @@
 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_MEMTEST=y