overlay: Add support for pipe dumps.

Add support for pipe state dump useful in dumpsys.
Reduce debug log spam when mdp state changes.

Change-Id: Ie27ad00698085e2ffd6166ad2f7503fe16a571f8
diff --git a/liboverlay/overlayMdpRot.cpp b/liboverlay/overlayMdpRot.cpp
index a802b4b..dc8ef09 100755
--- a/liboverlay/overlayMdpRot.cpp
+++ b/liboverlay/overlayMdpRot.cpp
@@ -272,4 +272,9 @@
     ALOGE("== Dump MdpRot end ==");
 }
 
+void MdpRot::getDump(char *buf, size_t len) const {
+    ovutils::getDump(buf, len, "MdpRotCtrl(msm_rotator_img_info)", mRotImgInfo);
+    ovutils::getDump(buf, len, "MdpRotData(msm_rotator_data_info)", mRotDataInfo);
+}
+
 } // namespace overlay