msm: mdss: Program unpack pattern for pipes with solidfill

When a pipe is staged with a solidfill color, we need to also
program the correct unpack pattern for the color format. If the
unpack pattern is not specified, the corresponding color layer may
not be display correctly.

Change-Id: Ic52fe29235813faa788745dd72f82edaca2635f1
Signed-off-by: Aravind Venkateswaran <aravindh@codeaurora.org>