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/liteboard_defconfig b/configs/liteboard_defconfig
index dbad009..ceae66a 100644
--- a/configs/liteboard_defconfig
+++ b/configs/liteboard_defconfig
@@ -22,7 +22,7 @@
 CONFIG_BOOTDELAY=1
 CONFIG_DEFAULT_FDT_FILE="imx6ul-liteboard.dtb"
 CONFIG_BOARD_EARLY_INIT_F=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_BOOTZ=y
 CONFIG_CMD_MEMTEST=y