drm/amdgpu: fix JPEG v5.0.0 queue reset failure in DPG mode

drm/amdgpu: fix JPEG v5.0.0 queue reset failure in DPG mode

In DPG mode jpeg_v5_0_0_ring_reset() takes the DPG stop path, which only
clears the JPEG_PG_MODE bit and never resets the JRBC. A hung ring is not
recovered: the post-reset ring test times out and the driver falls back to
a full MODE1 reset.

Temporarily force the static power-gating path during the reset so the
stop/start sequence power-cycles the JPEG block (JMI soft reset + power
off/on), matching the jpeg_v4_0 reset which has no DPG path.

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 79b3612827d1adcd2008cd585961fa35a6ff20f2)
Cc: stable@vger.kernel.org