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/mx6memcal_defconfig b/configs/mx6memcal_defconfig
index a860fbe..0be0b6a 100644
--- a/configs/mx6memcal_defconfig
+++ b/configs/mx6memcal_defconfig
@@ -16,7 +16,7 @@
 CONFIG_SUPPORT_RAW_INITRD=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=arch/arm/mach-imx/spl_sd.cfg,SPL"
 CONFIG_SPL_USB_HOST_SUPPORT=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_HUSH_PARSER=y
 # CONFIG_CMD_BOOTD is not set
 # CONFIG_CMD_BOOTM is not set