drm/amdgpu/: Add missing kdoc entry in amdgpu_vm_handle_fault function

drm/amdgpu/: Add missing kdoc entry in amdgpu_vm_handle_fault function

This commit adds a description for the 'ts' parameter in the
amdgpu_vm_handle_fault function's comment block.

Fixes the below with gcc W=1:
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c:2781: warning: Function parameter or struct member 'ts' not described in 'amdgpu_vm_handle_fault'

Cc: Xiaogang.Chen <Xiaogang.Chen@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202408251419.vgZHg3GV-lkp@intel.com/
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Xiaogang Chen <Xiaogang.Chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>