msm: kgsl: Remove 4xx support

Remove 4xx support from the msm-4.19 kernel. We are unlikely to see
any more targets from this family again and removing it also obsoletes
a number of larger workarounds and hacks that were made to accommodate
quirks in the 4xx family which will be removed in the following
patches.

Change-Id: Ic0dedbad890e9f9b20a9d3e1ea7a31d628323870
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>