[media] iguanair: simplify calculation of carrier delay cycles
Simplify the logic that calculates the carrier, and removes a warning
on avr32 arch:
drivers/media/rc/iguanair.c: In function 'iguanair_set_tx_carrier':
drivers/media/rc/iguanair.c:304: warning: 'sevens' may be used uninitialized in this function
Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com> Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>