drm/amd/amdgpu: Import amdgpu_amdkfd_gfx_v9 header file into implementation

[Why]
Prevent compiler warnings when building amdgpu kernel module

[How]
Add the include directive for amdgpu_amdkfd_gfx_v9 header file

Fixes: aeee2a48 ("drm/amd/amdgpu: Enable arcturus devices to access the method kgd_gfx_v9_get_cu_occupancy that is already defined")
Reviewed-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Signed-off-by: Ramesh Errabolu <Ramesh.Errabolu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reported-by: kernel test robot <lkp@intel.com>