msm_fb: display: Fix interleaved 422 input format register settings

Check to update chroma sample information in source format register is
based on fetch plane value, which does not take into account for
interleaved 422 input format. Remove this check and set chroma sample
values for RGB formats as well.

CRs-Fixed: 501035
Change-Id: If8fd47b6d47b326efd1cb70ce9701ac1d457dcfd
Signed-off-by: Mayank Chopra <makchopra@codeaurora.org>