msm: mdss: Fix the DSI lane swap programming logic

In the current programming sequence, if a particular logical lane
is not used, we map the corresponding physical lane for this to '0';
which means no connection. This can cause DSI FIFO overflow issues
for panels which don't use all the 4 lanes. Fix this by programming
the LOGICAL_LANE_SWAP_CTRL for all the 4 lanes always, irrespective
of the number of lanes used.

Change-Id: I31a703f8f5133eb85c33fd0d3728f824a435392d
Signed-off-by: Rashi Bindra <rbindra@codeaurora.org>