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/ls1046ardb_sdcard_defconfig b/configs/ls1046ardb_sdcard_defconfig
index a441d15..eceae9b 100644
--- a/configs/ls1046ardb_sdcard_defconfig
+++ b/configs/ls1046ardb_sdcard_defconfig
@@ -31,7 +31,7 @@
 CONFIG_SPL_ENV_SUPPORT=y
 CONFIG_SPL_I2C_SUPPORT=y
 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_CMD_DM=y
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_GPT=y