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/arch/arm/Kconfig b/arch/arm/Kconfig
index 2b5e7a8..1fd39a0 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -954,7 +954,7 @@
 	select SPL_SEPARATE_BSS if TARGET_SOCFPGA_SOC64
 	select SPL_SERIAL_SUPPORT
 	select SPL_SYSRESET
-	select SPL_WATCHDOG_SUPPORT
+	select SPL_WATCHDOG
 	select SUPPORT_SPL
 	select SYS_NS16550
 	select SYS_THUMB_BUILD if TARGET_SOCFPGA_GEN5 || TARGET_SOCFPGA_ARRIA10