mdss: mdp: release file node before process node when open fail

Releasing file node after process node causes the kernel
panic because process node is already freed. Correct order
to release nodes should be file node followed by process node
when PM API fails.

CRs-fixed: 753912
Change-Id: I252fc9eabaf0ba81d19b1989b03100849cdeca38
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>