[media] opera1: fix sparse warnings

drivers/media/usb/dvb-usb/opera1.c:557:29: warning: restricted __le16 degrades to integer
drivers/media/usb/dvb-usb/opera1.c:558:33: warning: restricted __le16 degrades to integer

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>