disp: msm: sde: decouple FETCH_PIPE_ACTIVE logic from setup_blendstages

Setup blendstages is done per LM but FETCH_PIPE_ACTIVE is per CTL.
Overloading mixer blendstage setup with fetch pipe logic can lead
to HW programming errors. Refactor the logic for setting
FETCH_PIPE_ACTIVE by adding a new op that allows caller to provide
a bitmask of all pipes required to be active on this CTL. This new
logic includes support for:
 - 4LM use-cases, staging pipes for all LMs within a CRTC
 - Demura fetch-pipe without need for tracking via active_cfg (removed)

Also, lower the cyclomatic complexity in setup_blendstages by moving
the logic for obtaining the mixer config settings in to a helper
function.

Change-Id: I2907b359ffad5734be5b06f44919b5ddb1ef3f7c
Signed-off-by: Steve Cohen <cohens@codeaurora.org>

msm/sde/sde_encoder.c

@@ -4232,7 +4232,7 @@ int sde_encoder_helper_reset_mixers(struct sde_encoder_phys *phys_enc,
 		/* only enable border color on LM */
 		if (phys_enc->hw_ctl->ops.setup_blendstage)
 			phys_enc->hw_ctl->ops.setup_blendstage(
-				phys_enc->hw_ctl, hw_lm->idx, NULL, NULL);
+				phys_enc->hw_ctl, hw_lm->idx, NULL);
 	}
 
 	if (!lm_valid) {