[PORT FROM R2] atomisp: Corrupt preview on changing zoom ratio in video mode

[PORT FROM R2] atomisp: Corrupt preview on changing zoom ratio in video mode

BZ: 20531

When the ISP is started from within the ISR context, the condition
of first invalid frame was not being handled properly. Therefore, a
corrupt frame was displayed when switching the video binaries. This
patch fixes this issue.

Change-Id: Ia73ae4d871db91fe6c37305d0164777d1f2a07a9
Orig-Change-Id: Idfccb6437ae181fedea1ab61412c59248b29054b
Signed-off-by: Lokesh Gupta <lokesh.gupta@intel.com>
Reviewed-on: http://android.intel.com:8080/30316
Reviewed-by: Koski, Anttu <anttu.koski@intel.com>
Reviewed-by: Kruger, Jozef <jozef.kruger@intel.com>
Reviewed-by: Cohen, David A <david.a.cohen@intel.com>
Reviewed-by: Wang, Wen W <wen.w.wang@intel.com>
Tested-by: Koski, Anttu <anttu.koski@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>
Reviewed-on: http://android.intel.com:8080/32444
Reviewed-by: Lampila, KalleX <kallex.lampila@intel.com>
Tested-by: Lampila, KalleX <kallex.lampila@intel.com>