watchdog: via_wdt: depends on PCI

via_wdt is a PCI driver so it should depend on PCI so that
it will not cause build errors.

drivers/watchdog/via_wdt.c:256:1: warning: data definition has no type or storage class
drivers/watchdog/via_wdt.c:256:1: warning: type defaults to 'int' in declaration of 'module_pci_driver'
drivers/watchdog/via_wdt.c:256:1: warning: parameter names (without types) in function declaration

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>