msm: mdss: add split link panel support in mdss

In split link panels, the four data lanes are split into
sublinks and the clock lane is shared among the sublink.
Add support for split link panels in mdss.

Change-Id: I40965c274a3591b0a00ca546052e7cb46967844d
Signed-off-by: Ashish Garg <ashigarg@codeaurora.org>