libs/gui: Update TRANSFORM HINT from BufferQueue

Read TRANFORM HINT value from Buffer Queue rather than STC.
STC's hint will be updated only when QueueBuffer is called.
So any query from client for hint in between two DequeueBuffer
call will read wrong value.

(cherry picked from commit 0618a92c24576e104043d139aaf92ecec2c0df88)

Change-Id: If3a244207e0584ee417deb36d357fe0ab7c1a96d