disp: msm: sde: avoid tx wait during DMS for targets with dsc rev2

This change removes tx_wait during DMS for targets which have
dsc_hw_rev_2. For targets with dsc_hw_rev_1, during DMS the
tx_wait is needed since DSC registers are not double buffered
and frame trigger needs to be serialized to avoid pp_timeout
issues.

Change-Id: I46479ed8713602d167e57c9d9d0f800f544607f2
Signed-off-by: Jayaprakash Madisetty <quic_jmadiset@quicinc.com>