hwc: Enable sync-pt for rotator on B-family

Enable sync-pt for rotator on B-family. The already existing
MSMFB_BUF_SYNC ioctl is used, with an extra member for session_id
from rotator.

Change-Id: Ib0ef6b1bc5cf1e6437090a217d7f731a3440f84b
diff --git a/liboverlay/overlayRotator.cpp b/liboverlay/overlayRotator.cpp
index 2995580..84a9818 100644
--- a/liboverlay/overlayRotator.cpp
+++ b/liboverlay/overlayRotator.cpp
@@ -174,11 +174,10 @@
 }
 
 int RotMgr::getRotDevFd() {
-    //2nd check just in case
-    if(mRotDevFd < 0 && Rotator::getRotatorHwType() == Rotator::TYPE_MDP) {
-        mRotDevFd = ::open("/dev/msm_rotator", O_RDWR, 0);
+    if(mRotDevFd < 0 && Rotator::getRotatorHwType() == Rotator::TYPE_MDSS) {
+        mRotDevFd = ::open("/dev/graphics/fb0", O_RDWR, 0);
         if(mRotDevFd < 0) {
-            ALOGE("%s failed to open rotator device", __FUNCTION__);
+            ALOGE("%s failed to open fb0", __FUNCTION__);
         }
     }
     return mRotDevFd;