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/x530_defconfig b/configs/x530_defconfig
index 0ff0956..90798a3 100644
--- a/configs/x530_defconfig
+++ b/configs/x530_defconfig
@@ -26,7 +26,7 @@
 CONFIG_SILENT_CONSOLE_UPDATE_ON_RELOC=y
 CONFIG_MISC_INIT_R=y
 CONFIG_SPL_BOARD_INIT=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_CMD_MEMINFO=y
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_GPIO=y