msm: kgsl: Fix leak when preemption init fails

For any reason if preemption initialization fails,
we do not free allocated memory for preemption.
Free allocated memory when it fails.

Change-Id: Ie931766f1ec1de7f3a0522054fc1fcb7b9426be6
Signed-off-by: Prakash Kamliya <pkamliya@codeaurora.org>