watchdog: ebc-c384_wdt: Allow build for X86_64

watchdog: ebc-c384_wdt: Allow build for X86_64

With the introduction of the ISA_BUS_API Kconfig option, ISA-style
drivers may be built for X86_64 architectures. This patch changes the
ISA Kconfig option dependency of the WinSystems EBC-C384 watchdog timer
driver to ISA_BUS_API, thus allowing it to build for X86_64 as it is
expected to.

Cc: Wim Van Sebroeck <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]>
Signed-off-by: William Breathitt Gray <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>