[media] saa7164: free_irq before pci_disable_device

Free the IRQ before disabling the device. Otherwise errors like this when unloading the module:

[21135.458560] ------------[ cut here ]------------
[21135.458569] WARNING: CPU: 4 PID: 1696 at /home/apw/COD/linux/fs/proc/generic.c:521 remove_proc_entry+0x1a1/0x1b0()
[21135.458572] remove_proc_entry: removing non-empty directory 'irq/47', leaking at least 'saa7164[0]'

Signed-off-by: Olli Salonen <olli.salonen@iki.fi>
Reviewed-by: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>