ide: call clear_irq() method in ide_timer_expiry()

Now the clear_irq() method is called only from ide_intr() but ide_timer_expiry()
also should call this method in case when drive_is_ready() succeeds...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>