media: soc_camera: add cam_gpio support in OV5693

media: soc_camera: add cam_gpio support in OV5693

In 6 camera sensor board E2128 has 6 OV5693. CAM A and CAM B share
GPIO for power down. CAM C and CAM D share GPIO for power down.

Normal gpio API can't handle this use case, so add cam_gpio support.

Bug 1629720

Change-Id: Ie6387525dea4248b68e9e54ce22cfcf08266a251
Signed-off-by: Bryan Wu <pengw@nvidia.com>
Reviewed-on: http://git-master/r/724385
(cherry picked from commit b8f1b183707b0ca6ab5ddc8d3c597af75c18964a)
Reviewed-on: http://git-master/r/729155
GVS: Gerrit_Virtual_Submit
Reviewed-by: Winnie Hsu <whsu@nvidia.com>