sdm: drm: Fix h_blanking accounting in SDM

DRM driver provides the total h_blanking for the display. So, on a
display with dual DSI panels, DRM driver has already accounted for
both panels, hence SDM should not account for h_blanking per panel.

CRs-Fixed: 2092799
Change-Id: I621cf6de225a3caeb5f5c93d1e7c6b47e86a2fa2
1 file changed