disp: msm: sde: use drm mode set by user-mode in trusted-vm

Trusted-vm uses the cont-splash path to initialize the software
states by reading the hardware registers and populating the
SDE & DRM software states. But drm mode cannot be determined by
register reads, so rely on user-mode to get the mode which comes
as part of the first atomic_commit check phase which handles the
transition. The primary-vm user-mode passes the current mode to
trusted-vm through qrtr which is in-turn passed to driver to
set that particular mode.

Change-Id: I4fb86b40b8a0583c8edb539b0a51dcd33de731ff
Signed-off-by: Veera Sundaram Sankaran <veeras@codeaurora.org>