drm/amdkfd: Fix if preprocessor statement above kfd_fill_iolink_info_for_cpu

Clang warns:

drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_crat.c:866:5: warning:
'CONFIG_X86_64' is not defined, evaluates to 0 [-Wundef]
    ^
1 warning generated.

Fixes: d1c234e2

 ("drm/amdkfd: Allow building KFD on ARM64 (v2)")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>