[media] omap3isp: Use devm_* managed functions

Replace kzalloc, request_mem_region, ioremap, clk_get and regulator_get
with their devm_* managed replacement.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>