drm/msm/sde: allow PM_QOS vote for all command mode panels

Currently, QOS is requested for primary panel only. As dual
DSI panel is now supported, QOS needs to be requested for
multiple panels. Remove the check for primary panel only so
that QOS can be requested for multiple command mode panels.

CRs-Fixed: 2254681
Change-Id: I90a7aba0221238c4a4366628a9d5d24b6f5206a8
Signed-off-by: Ajay Singh Parmar <aparmar@codeaurora.org>