drm/amdgpu: print an error when the parser can't be initialized

Similar to other error messages, might help for tracking down
issues.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>