[media] omap3isp: Add set performance callback in isp platform data

Replace the omap_pm_set_min_bus_tput() with a callback to board code.
This makes the omap3isp driver compilable as a module, and lets board
code manage OMAP PM details depending on board requirements.

Signed-off-by: Stanimir Varbanov <svarbanov@mm-sol.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>