msm: display: display idle checking update

msm_fb_blank_sub might be called for UNBLANK from
display update work queue, which is at commit state.
Idle detection is invalid in this situation
Add detection for external snd earlyuspend/resume interface.

Change-Id: I1b08d10c9c494b9b3df5e95c4a54036877d5653f
Signed-off-by: Ken Zhang <kenz@codeaurora.org>