kgsl/drm: Fix resource leakage when there are some errors

There are some resource leakage cases when error is occurred.
This patch fixes them.

Change-Id: I914e36a2dbb21e642d818dcb0d67c3e605c54c2a
Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Signed-off-by: Mathew Karimpanal <kjmathew@codeaurora.org>
(cherry picked from commit c37499fe7cf10cca0a1f97536a7b68ad3a2ff0fb)