hwc: Don't validate dropped layers for MDP support

Ignore dropped layers while checking MDP support for layers
when trying for full MDP composition.

Change-Id: Ia11594173759e9dcc321d72ef425615281c35b7c
diff --git a/libhwcomposer/hwc_mdpcomp.cpp b/libhwcomposer/hwc_mdpcomp.cpp
index 581f57c..23f9154 100644
--- a/libhwcomposer/hwc_mdpcomp.cpp
+++ b/libhwcomposer/hwc_mdpcomp.cpp
@@ -613,7 +613,8 @@
     const int numAppLayers = ctx->listStats[mDpy].numAppLayers;
     for(int i = 0; i < numAppLayers; i++) {
         hwc_layer_1_t* layer = &list->hwLayers[i];
-        if(not isSupportedForMDPComp(ctx, layer)) {
+        if(not mCurrentFrame.drop[i] and
+           not isSupportedForMDPComp(ctx, layer)) {
             ALOGD_IF(isDebug(), "%s: Unsupported layer in list",__FUNCTION__);
             return false;
         }