drm/amdgpu: use amdgpu_ras.h in amdgpu_debugfs.c

include amdgpu_ras.h head file instead of use extern
ras_debugfs_create_all function

Signed-off-by: Stanley.Yang <Stanley.Yang@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>