drm/amdgpu: fix compiler 'side-effect' check issue for RAS_EVENT_LOG()

create a new helper function to avoid compiler 'side-effect'
check about RAS_EVENT_LOG() macro.

Signed-off-by: Yang Wang <kevinyang.wang@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>