ANDROID: clean up remaining merge issue from drm/msm/a6xx.c patch

The patch "FROMLIST: drm/msm/a6xx: Use the DMA API for GMU memory
objects" is merged upstream, but when merging from there, one tiny bit
was left over in our tree.  Revert that as it's not needed here.

Cc: Jordan Crouse <jcrouse@codeaurora.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/lkml/1582223216-23459-5-git-send-email-jcrouse@codeaurora.org/


Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I4078855b7efb732c52e0dac2febe9389f39aec8e