amdgpu: fix not to add amdgpu.ids when building without amdgpu

The amdgpu.ids is only required when building with amdgpu support.
Fix not to add it without amdgpu.

Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>