dev-amdgpu: Handle ring buffer wrap for PM4 queue

Change-Id: I27bc274327838add709423b072d437c4e727a714
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/65431
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
(cherry picked from commit 623e2d3dac3e75c67b4e1b8f6a7113f0ab376960)
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/65452
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>