drm/msm: support probe deferral in msm_drv

Make fixes to support probe deferral in msm_drv, display
manager, and sde_kms. Move initialization logic out of msm_drv
probe and into load call so it is paired with unload.

Change-Id: I9330d61de8f6188cb0e9769d569d5cff841cb159
Signed-off-by: Lloyd Atkinson <latkinso@codeaurora.org>