msm: mdss: release process resources on fb close

Track overlays/rotator sessions created for each process and make sure
these are released during fb close. This can handle cases where crash
happens on a process that owns the resources, but panel wouldn't be
blanked due to other process still holding a reference to fb.

CRs-Fixed: 511804
Change-Id: Ib3b8b57c871f91c59e1bef36cd94b7d957185050
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>