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/pcm058_defconfig b/configs/pcm058_defconfig
index 3f14326..a681af2 100644
--- a/configs/pcm058_defconfig
+++ b/configs/pcm058_defconfig
@@ -37,7 +37,7 @@
 CONFIG_SPL_FS_EXT4=y
 CONFIG_SPL_DM_SPI_FLASH=y
 CONFIG_SPL_SPI_LOAD=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_SPL_YMODEM_SUPPORT=y
 # CONFIG_CMD_FLASH is not set
 CONFIG_CMD_GPIO=y