drm/amdgpu: fix JPEG v4.0.5 queue reset failure in DPG mode

drm/amdgpu: fix JPEG v4.0.5 queue reset failure in DPG mode

Like jpeg_v5_0_0, in DPG mode the ring reset path only clears the
JPEG_PG_MODE bit and never resets a hung JRBC, so 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.

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 75a308eef4503a9d2bf297bef5a9317d2209e696)
Cc: stable@vger.kernel.org