alpha: Fix breakage in wdt_pci

drivers/watchdog/wdt_pci.c: In function 'wdtpci_ctr_mode':
drivers/watchdog/wdt_pci.c:120: error: implicit declaration of function 'udelay'
{standard input}: Assembler messages:

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>