V4L/DVB: media: ir-keytable: null dereference in debug code

"ir_dev->props" can be NULL.  We only use raw mode if "ir_dev->props" is
non-NULL and "ir_dev->props->driver_type == RC_DRIVER_IR_RAW".

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>