Revert "msm: kgsl: Add per context timestamp"

This reverts commit 2a811252c73a9beae002c95cdeef974f8be0579f.

Change-Id: Ic3018f19eb1a089ae67e0f3c253cc00e7d0285e3
Signed-off-by: Wei Zou <wzou@codeaurora.org>
diff --git a/drivers/gpu/msm/kgsl_snapshot.c b/drivers/gpu/msm/kgsl_snapshot.c
index c24576d..cfcb2ea 100644
--- a/drivers/gpu/msm/kgsl_snapshot.c
+++ b/drivers/gpu/msm/kgsl_snapshot.c
@@ -64,7 +64,7 @@
 
 	header->timestamp_queued = -1;
 	header->timestamp_retired = device->ftbl->readtimestamp(device,
-		context, KGSL_TIMESTAMP_RETIRED);
+		KGSL_TIMESTAMP_RETIRED);
 
 	_ctxtptr += sizeof(struct kgsl_snapshot_linux_context);