disp: msm: sde: Allow for overriding CP features flush mechanism

Allow for overriding color processing features that normally uses
DSPP flush to use LM flush instead. This is required on targets
where some of the DSPP features have been tied to LM flush bits.

This changes adds a field in color processing node to track if the
override is needed and enables LM flush override for rounded corner
on target requiring it.

Change-Id: I584bd7b20dfc9fc7795b1b3b10e2f17a82945ce4
Signed-off-by: Amine Najahi <anajahi@codeaurora.org>