media: atmel-isc: Enable the clocks during probe

To meet the relationship, enable the HCLOCK and ispck during the
device probe, "isc_pck frequency is less than or equal to isc_ispck,
and isc_ispck is greater than or equal to HCLOCK."
Meanwhile, call the pm_runtime_enable() in the right place.

Signed-off-by: Wenyou Yang <wenyou.yang@microchip.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>