hwc: mdpcomp: Use actual usable mixer stages from driver

The driver now sends the actual usable mixer stages, so no need to
deduct the STAGE_UNUSED and STAGE_BASE.

Change-Id: I3690d10b5ccf83cab499871479768fcd5cdb2a4e
diff --git a/libhwcomposer/hwc_mdpcomp.cpp b/libhwcomposer/hwc_mdpcomp.cpp
index 975c195..4e7d101 100644
--- a/libhwcomposer/hwc_mdpcomp.cpp
+++ b/libhwcomposer/hwc_mdpcomp.cpp
@@ -131,9 +131,7 @@
 
     qdutils::MDPVersion &mdpVersion = qdutils::MDPVersion::getInstance();
 
-    /* MDSS_MDP_STAGE_UNUSED and MDSS_MDP_STAGE_BASE are not available for MDP
-     * composition. */
-    sMaxPipesPerMixer = (int)mdpVersion.getBlendStages() - 2;
+    sMaxPipesPerMixer = (int)mdpVersion.getBlendStages();
     if(property_get("persist.hwc.mdpcomp.maxpermixer", property, "-1") > 0) {
         int val = atoi(property);
         if(val >= 0)
@@ -231,7 +229,7 @@
 
 void MDPComp::setMaxPipesPerMixer(const uint32_t value) {
     qdutils::MDPVersion &mdpVersion = qdutils::MDPVersion::getInstance();
-    uint32_t maxSupported = (int)mdpVersion.getBlendStages() - 2;
+    uint32_t maxSupported = (int)mdpVersion.getBlendStages();
     if(value > maxSupported) {
         ALOGW("%s: Input exceeds max value supported. Setting to"
                 "max value: %d", __FUNCTION__, maxSupported);