media: ov9650: Drop platform data code path

Nothing in the kernel uses the platform data code path.
Drop it, and drop the use of the old legacy <linux/gpio.h>
API in the process.

Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>