watchdog: Migrate OMAP_WATCHDOG to Kconfig

Move this entry to Kconfig.  As it is a hardware watchdog, select
HW_WATCHDOG.  While we could default to enabling this for all platforms,
it is currently only enabled by default on AM33XX, so keep that logic
today.

Cc: Roger Meier <r.meier@siemens.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/brppt1_mmc_defconfig b/configs/brppt1_mmc_defconfig
index 7d92c13..1bdbf90 100644
--- a/configs/brppt1_mmc_defconfig
+++ b/configs/brppt1_mmc_defconfig
@@ -57,4 +57,5 @@
 CONFIG_USB_STORAGE=y
 CONFIG_SYS_WHITE_ON_BLACK=y
 CONFIG_LCD=y
+CONFIG_OMAP_WATCHDOG=y
 CONFIG_OF_LIBFDT=y