V4L/DVB (6382): saa7134: fix NULL dereference at suspend time for cards without IR receiver

Calling saa7134_ir_stop at suspend is no good idea
for saa7134 cards without remote control.

Signed-off-by: Matthias Schwarzott <zzam@gentoo.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>