msm: mdss:To fix race condition during mdp debugfs release

To fix race condition in the release of the mdp debugfs functions
panel_debug_base_release and mdss_debug_base_release by adding
the lock for unpreempted freeing of the buffer so that multiple
concurrent processes cannot affect the release which can possibly
lead to use-after-free operation on the buffer.

Bug: 33863407
Change-Id: I348de6408b5fe7d41d9671c4d0956c0944f828bb