msm: kgsl: add kgsl_sync_fence_waiter for server side sync

For server side sync the KGSL kernel module needs to perform
an asynchronous wait for a fence object prior to issuing
subsequent commands.

Change-Id: I1ee614aa3af84afc4813f1e47007f741beb3bc92
Signed-off-by: Jeff Boody <jboody@codeaurora.org>
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>