msm: kgsl: Remove enhanced memory accounting

Remove some memory accounting that is unsupported in the upstream kernel.
If the feature that used these statistics returns then these can be
easily returned to their rightful places.

Change-Id: Ic0dedbadf56ab28d6610d52ab6e901dc8f9dadff
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>