media: iguanair: add sanity checks

The driver needs to check the endpoint types, too, as opposed
to the number of endpoints. This also requires moving the check earlier.

Reported-by:  <syzbot+01a77b82edaa374068e1@syzkaller.appspotmail.com>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>