hwc: Reset ROI and avoid dirtyRect for video case

Reset ROI in when we are unable to proceed with full MDP comp.
Do not use dirtyRect for video use-cases to address some
corner cases.

Change-Id: Id1ea6c1515f4441f0f35c0d08828e9c361bcbc86
diff --git a/libhwcomposer/hwc_mdpcomp.cpp b/libhwcomposer/hwc_mdpcomp.cpp
index d921f8f..06fba61 100755
--- a/libhwcomposer/hwc_mdpcomp.cpp
+++ b/libhwcomposer/hwc_mdpcomp.cpp
@@ -176,6 +176,12 @@
     mCurrentFrame.reset(numLayers);
     ctx->mOverlay->clear(mDpy);
     ctx->mLayerRotMap[mDpy]->clear();
+    ctx->listStats[mDpy].roi.x = 0;
+    ctx->listStats[mDpy].roi.y = 0;
+    ctx->listStats[mDpy].roi.w = (int)ctx->dpyAttr[mDpy].xres;
+    ctx->listStats[mDpy].roi.h = (int)ctx->dpyAttr[mDpy].yres;
+    memset(&mCurrentFrame.drop, 0, sizeof(mCurrentFrame.drop));
+    mCurrentFrame.dropCount = 0;
 }
 
 void MDPComp::reset() {