hwc: Call MSMFB_DISPLAY_COMMIT even if FB handle is null.

Call MSMFB_DISPLAY_COMMIT for primary FB even if FB handle is null.
This is already done for external FB.

Change-Id: I5c405f933ce0fd99df6813acea45169802c54226
diff --git a/libhwcomposer/hwc.cpp b/libhwcomposer/hwc.cpp
index 130f263..6a0e0ee 100644
--- a/libhwcomposer/hwc.cpp
+++ b/libhwcomposer/hwc.cpp
@@ -332,10 +332,10 @@
                     ret = -1;
                 }
             }
-            if (ctx->mFbDev->post(ctx->mFbDev, fbLayer->handle)) {
-                ALOGE("%s: ctx->mFbDev->post fail!", __FUNCTION__);
-                return -1;
-            }
+        }
+        if (ctx->mFbDev->post(ctx->mFbDev, fbLayer->handle)) {
+            ALOGE("%s: ctx->mFbDev->post fail!", __FUNCTION__);
+            return -1;
         }
     }
     return ret;