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/kp_imx6q_tpc_defconfig b/configs/kp_imx6q_tpc_defconfig
index e0ca926..e818f00 100644
--- a/configs/kp_imx6q_tpc_defconfig
+++ b/configs/kp_imx6q_tpc_defconfig
@@ -31,7 +31,7 @@
 CONFIG_SYS_CONSOLE_OVERWRITE_ROUTINE=y
 CONFIG_SPL_RAW_IMAGE_SUPPORT=y
 CONFIG_SPL_POWER=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 # CONFIG_CMD_ELF is not set
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_I2C=y