msm: display: add more checking to ensure display is idle

Before execute operation on display, make sure it is complete idle
Because non-blocking display update has been introduced, need make sure
display update has finished in all entrances except the ones for
initialization.

(cherry picked from commit 43d62bf4b61cbaf52677126a4899ff8b489cdd76)

Change-Id: I18bee54c950404bea7ab89c9575c888e4c015935
Signed-off-by: Ken Zhang <kenz@codeaurora.org>
Signed-off-by: Siddhartha Agrawal <agrawals@codeaurora.org>