disp: msm: sde: fix the dcwb allocation

This change retrieves the dcwb_idx from hw_pp
to get proper hw block. The 'commit 6bb958c88b23
("disp: msm: sde: fix dcwb idx selection for pp_dither
and CTL blocks")' has missed updating dcwb_idx in
cwb flush helper API while porting 'commit 85c5ca9790b3
("disp: msm: sde: fix dcwb idx selection for dither
and CTL blocks")'. Underruns are seen while configuring
cwb dither in mid tier targets as dcwb pp block counter
can be different.

Change-Id: Iaabbb5b3724592998894b88f36e19c978d3f8306
Signed-off-by: Gaurav LNU <[email protected]>

msm/sde/sde_encoder_phys_wb.c

@@ -1453,7 +1453,7 @@ static void _sde_encoder_phys_wb_update_cwb_flush_helper(
 		src_pp_idx = (enum sde_cwb) (src_pp_idx + i);
 
 		if (test_bit(SDE_WB_DCWB_CTRL, &hw_wb->caps->features)) {
-			dcwb_idx = (enum sde_dcwb) ((hw_pp->idx - (PINGPONG_CWB_0 - 1)) + i);
+			dcwb_idx = hw_pp->dcwb_idx + i;
 			if ((test_bit(SDE_WB_CWB_DITHER_CTRL, &hw_wb->caps->features)) &&
 				hw_wb->ops.program_cwb_dither_ctrl){
 				hw_wb->ops.program_cwb_dither_ctrl(hw_wb,