msm: mdp: Update sync pt. behaviour

Add a retire fence and clean up the existing release fence
implementation

Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>

Change-Id: Idc999a2a8fc58f5cdcbad78938a4857bf3a9d178
Merge pull request #1 from CyanogenMod/cm-10.2

msm: mdp: Update sync pt. behaviour