drm/amdgpu: Fix ARM compilation warning

drm/amdgpu: Fix ARM compilation warning

Fix this ARM warning:

drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c:664:35: warning: format '%ld'
expects argument of type 'long int', but argument 4 has type 'size_t' {aka
'unsigned int'} [-Wformat=]

Cc: Alex Deucher <Alexander.Deucher@amd.com>
Cc: kbuild-all@lists.01.org
Cc: linux-kernel@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 43222aa52382 ("drm/amdgpu: Show IP discovery in sysfs")
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Acked-by: Alex Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>