drm/msm/a6xx: Improve gpu recovery sequence

We can do a few more things to improve our chance at a successful gpu
recovery, especially during a hangcheck timeout:
1. Halt CP and GMU core
2. Do RBBM GBIF HALT sequence
3. Do a soft reset of GPU core

Signed-off-by: Akhil P Oommen <quic_akhilpo@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/498400/
Link: https://lore.kernel.org/r/20220819015030.v5.6.Idf2ba51078e87ae7ceb75cc77a5bd4ff2bd31eab@changeid


Signed-off-by: Rob Clark <robdclark@chromium.org>