drm/amdgpu: Fix inconsistent of format with argument type in amdgpu_xgmi.c

Fix follow warning:
[drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c:249]: (warning) %d in format
string (no. 1) requires 'int' but the argument type is 'unsigned int'.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>