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/ls1021aqds_nand_defconfig b/configs/ls1021aqds_nand_defconfig
index a1c1847..72c459e 100644
--- a/configs/ls1021aqds_nand_defconfig
+++ b/configs/ls1021aqds_nand_defconfig
@@ -33,7 +33,7 @@
 CONFIG_SPL_I2C_SUPPORT=y
 CONFIG_SPL_MPC8XXX_INIT_DDR_SUPPORT=y
 CONFIG_SPL_NAND_SUPPORT=y
-CONFIG_SPL_WATCHDOG_SUPPORT=y
+CONFIG_SPL_WATCHDOG=y
 CONFIG_HUSH_PARSER=y
 CONFIG_CMD_BOOTZ=y
 CONFIG_CMD_IMLS=y