drm/amdgpu: Use parentheses for sizeof *numa_info in 'amdgpu_acpi_get_numa_info'

Fixes the below:

WARNING: sizeof *numa_info should be sizeof(*numa_info)

Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>