disp: msm: dp: skip link training in simulation mode

Skip link training when in simulation mode considering that we
are not yet implementing tests specific to link training. This
change will reduce the time it takes to power on the panel in
simulation mode, and also reduce the likelihood of failures
caused by unresponsive host machines.

Change-Id: Ie215cafd545bb25b4a033ceae1f275c690e7433d
Signed-off-by: Tatenda Chipeperekwa <tatendac@codeaurora.org>