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/udoo_defconfig b/configs/udoo_defconfig
index 791613e..522d55c 100644
--- a/configs/udoo_defconfig
+++ b/configs/udoo_defconfig
@@ -24,7 +24,7 @@
 CONFIG_BOARD_EARLY_INIT_F=y
 CONFIG_SPL_FS_EXT4=y
 CONFIG_SPL_I2C_SUPPORT=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_MMC=y
 # CONFIG_CMD_PINMUX is not set