[media] az6027: get rid of warning: no previous prototype

drivers/media/usb/dvb-usb/az6027.c:1054:5: warning: no previous prototype for 'az6027_identify_state' [-Wmissing-prototypes]
drivers/media/usb/dvb-usb/az6027.c:301:5: warning: no previous prototype for 'az6027_usb_in_op' [-Wmissing-prototypes]

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