atomisp: fix runtime PM issues

atomisp: fix runtime PM issues

BZ: 23514

Fix 'Unbalanced pm_runtime_enable' issue by removing such call from driver
as PCI core already calls it for each device. In addition, enable runtime
PM for camera by default so that it does not block PM.

Change-Id: I7f60d8a9b9330b6a324a4435d7b57ff8a78a48ab
Signed-off-by: Yong Wang <yong.y.wang@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-on: http://android.intel.com:8080/34938
Reviewed-by: Shevchenko, Andriy <andriy.shevchenko@intel.com>
Reviewed-by: Toivonen, Tuukka <tuukka.toivonen@intel.com>
Reviewed-by: Wang, Wen W <wen.w.wang@intel.com>
Reviewed-by: Cohen, David A <david.a.cohen@intel.com>
Tested-by: Koski, Anttu <anttu.koski@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>