[media] siano: remove a bogus printk line

The logic that detects the types of sms devices is bogus. It returns
	[ 4645.187790] smsusb_init_device: line: 372: Unspecified sms device type!
For several devices, including the one I have (SMS_RIO). In a matter
of fact, the right thing to do there is to print an error only if
the device is really unknown (SMS_UNKNOWN_TYPE).

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>