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/imx6ul_isiot_emmc_defconfig b/configs/imx6ul_isiot_emmc_defconfig
index a3e7768..be7bf0e 100644
--- a/configs/imx6ul_isiot_emmc_defconfig
+++ b/configs/imx6ul_isiot_emmc_defconfig
@@ -24,7 +24,7 @@
 CONFIG_SUPPORT_RAW_INITRD=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=arch/arm/mach-imx/spl_sd.cfg"
 CONFIG_BOOTDELAY=3
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="isiotmx6ul> "
 CONFIG_CRC32_VERIFY=y