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/brppt1_mmc_defconfig b/configs/brppt1_mmc_defconfig
index b832ffe..2ad0986 100644
--- a/configs/brppt1_mmc_defconfig
+++ b/configs/brppt1_mmc_defconfig
@@ -34,7 +34,7 @@
 CONFIG_SPL_I2C_SUPPORT=y
 # CONFIG_SPL_NAND_SUPPORT is not set
 CONFIG_SPL_POWER=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_SPL_YMODEM_SUPPORT=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_BOOTZ=y