disp: msm: dp: use VESA recommended default dsc slice height

By default use a slice height of 108 lines as it provides better
performance while maximizing compression and avoiding creating
artifacts at the slice boundary. This value is the recommended
one in VESA DSC specification and it is required for DP DSC CTS
tests with CRC validation to PASS.

Change-Id: I5c295873e4cf79f9fcf2da167a2349289118783b
Signed-off-by: Amine Najahi <anajahi@codeaurora.org>