msm: kgsl: Rename PM4 to CP to better align with A3XX code

The A3XX code likes to use CP_ as a prefix for ringbuffer
commands rather then the legacy PM4 prefix.  Since it is more
correct, switch the A2XX code over now to make it easier to
integrate A3XX into the mix.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
6 files changed