drm/amdgpu: Fix core reset sequence for JPEG4_0_3

For cores 1 through 7 repair the core reset sequence by
adjusting offsets to access the expected registers.

Signed-off-by: Sathishkumar S <sathishkumar.sundararaju@amd.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>