[media] smiapp: Switch to gpiod API for GPIO control

Switch from the old gpio API to the new descriptor based gpiod API.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>