msm: kgsl: Add support for the Adreno GPU

First take a snapshot of the Adreno GPU (KGSL) driver from msm-4.19
commit 963db0f98552 ("msm: ipa4: add generic header processing context").

Then copy the msm_adreno_devfreq.h header from its previous location in
include/linux and the user API header from include/uapi/linux into the
driver directory. Both these files no longer need to be in the "generic"
headers.

Next do cleanups, lots of cleanups. Remove a bunch of extra features that
are from long departed targets or that have otherwise been replaced and
improved.

And finally cleanup kernel APIs that are no longer used, remove the
exported symbols from the GPU driver since nobody depends on us and do a
few other minor bits to put us on a track to being friendly with a modern
kernel.

Change-Id: Ic0dedbad5200dd9359a7b2fc06de415d755934e9
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>