V4L/DVB (3738): Saa7134: Fix oops with disable_ir=1

When disable_ir=1 parameter is used, or when saa7134_input_init1()
fails for any other reason, dev->remote will remain NULL, and the
driver will oops in saa7134_hwinit2().  Therefore dev->remote must be
checked before dereferencing.

Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>