drm/amdgpu/jpeg4: add additional ring reset error checking

Start and stop can fail, so add checks.

Fixes: 74894ffc ("drm/amdgpu: Add ring reset callback for JPEG4_0_0")
Reviewed-by: Sathishkumar S <sathishkumar.sundararaju@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Sathishkumar S <sathishkumar.sundararaju@amd.com>