drm/msm: ensure msm_drm probe and eDRM Probe completion

There are issues when display driver probe() execution is scheduled
out during kernel boot because probe_type marked as
PROBE_PREFER_ASYNCHRONOUS.
Since there are few kernel modules that needs display driver to be
initialized. This change adds late_initcall() function which waits
for the completion of probes() to ensure that display is
initialized before other kernel module which can impact the system
boot behavior.

Change-Id: Idd83ac0450ed6f8e09dc98de8bbcec05942302e7
Signed-off-by: Rahul Sharma <rahsha@codeaurora.org>