drm/msm/dp: update the swing and pre-emphasis values for sm8150

Update the values for the voltage swing and pre-emphasis
levels used when programming the DP PHY during the link power
on sequence.

Change-Id: I99e4d515796fd14f9328fc53be3081f934a67f4c
Signed-off-by: Tatenda Chipeperekwa <tatendac@codeaurora.org>