[media] v4l: vsp1: Don't handle clocks manually

The power domain performs functional clock handling when using runtime
PM, there's no need to enable and disable the clock manually.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>