platform/x86: asus-tf103c-dock: Make 2 global structs static

tf103c_dock_hid_ll_driver and tf103c_dock_pm_ops are not used outside of
the driver, make them both static.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20220117112644.260168-2-hdegoede@redhat.com