msm: kgsl: Hold driver process mutex till sysfs entries deleted

sysfs entries deletion logic is not under the driver
process mutex lock, there was a Camera test case
where a single process was trying to call
kgsl_open/kgsl_release very rapidly from multiple
thread, sometimes sysfs entries remained valid
and kgsl_open was trying to create new sysfs
entries for same process id. This caused
WARNING in kernel logs "sysfs: cannot create
duplicate filename '/devices/virtual/kgsl/kgsl/proc/277'"
This change holds the driver process mutex
lock till sysfs entries are deleted.

Change-Id: I0f66314e704c2b53657961303f76e2bd4f34e5b5
Signed-off-by: Prakash Kamliya <pkamliya@codeaurora.org>

drivers/gpu/msm/kgsl.c

@@ -838,8 +838,6 @@ static void kgsl_destroy_process_private(struct kref *kref)
 		mutex_unlock(&kgsl_driver.process_mutex);
 		return;
 	}
-	list_del(&private->list);
-	mutex_unlock(&kgsl_driver.process_mutex);
 
 	if (private->kobj.parent)
 		kgsl_process_uninit_sysfs(private);
@@ -863,6 +861,9 @@ static void kgsl_destroy_process_private(struct kref *kref)
 	kgsl_mmu_putpagetable(private->pagetable);
 	idr_destroy(&private->mem_idr);
 
+	list_del(&private->list);
+	mutex_unlock(&kgsl_driver.process_mutex);
+
 	kfree(private);
 	return;
 }