msm: kgsl: Return correct error code if HFI write fails

Return the result of trying to write to the HFI queue
to the caller. Then the caller can take the appropriate
action based on what the failure was.

Change-Id: I591c0e3fc78becf03e30df8fcca206f0e281bbfb
Signed-off-by: Carter Cooper <ccooper@codeaurora.org>