[media] platform drivers: Fix build on frv arch

[media] platform drivers: Fix build on frv arch

On frv, the following errors happen:
	drivers/media/platform/soc_camera/rcar_vin.c: In function 'rcar_vin_setup':
	drivers/media/platform/soc_camera/rcar_vin.c:284:3: error: implicit declaration of function 'iowrite32' [-Werror=implicit-function-declaration]
	drivers/media/platform/soc_camera/rcar_vin.c: In function 'rcar_vin_request_capture_stop':
	drivers/media/platform/soc_camera/rcar_vin.c:353:2: error: implicit declaration of function 'ioread32' [-Werror=implicit-function-declaration]
This is because this driver forgot to include linux/io.h.

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>