mt9e013: async power up sequence to decrease Lanuch2preview time

mt9e013: async power up sequence to decrease Lanuch2preview time

BZ: 32405

Currently power up time for mt9e013 takes about 130ms which blocks the v4l2 call
of S_INPUT, since sensor subdev call s_power is called from it. And hense impact
the overall lunch2preview performance.

This patch makes s_power subdev call create a workthread to do the
time-consuming power up procedure and return immediately, which will
not block the s_input and also let the power up procedure can be run
in parallel with other initializations. For other subdev calls that
access sensor hw and need sensor power up to be done, e.g.: s_mbus_fmt,
s_ctrl, g_ctrl, etc, it will check and wait for the power up workthread
to be finished.

Change-Id: I31ef1307c82f4a516aad78409b4881b2aa53469f
Signed-off-by: Tao Jing <jing.tao@intel.com>
Signed-off-by: ziyux.jiang <ziyux.jiang@intel.com>
Reviewed-on: http://android.intel.com:8080/44109
Reviewed-by: Bhat, Sheethal <sheethal.bhat@intel.com>
Reviewed-by: Wang, Wen W <wen.w.wang@intel.com>
Reviewed-by: Lampila, KalleX <kallex.lampila@intel.com>
Tested-by: Lampila, KalleX <kallex.lampila@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>