watchdog: designware: Make this depend on WDT

watchdog: designware: Make this depend on WDT

As this driver can dynamically determine the values set in
CONFIG_DW_WDT_BASE when using WDT, so make this depend on WDT rather
than migrate CONFIG_DW_WDT_BASE to Kconfig.

Cc: Chee Tien Fong <tien.fong.chee@intel.com>
Cc: Chin-Liang See <chin.liang.see@intel.com>
Cc: Dinh Nguyen <dinh.nguyen@intel.com>
Cc: Holger Brunck <holger.brunck@hitachienergy.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Siew Chin Lim <elly.siew.chin.lim@intel.com>
Cc: Stefan Roese <sr@denx.de>
Cc: hee Hong Ang <chee.hong.ang@intel.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Stefan Roese <sr@denx.de>