The 258a:6a88 keyboard-dock shipped with the Prowise PT301 tablet is
likely another ITE based design. The controller die is directly bonded
to the PCB with a blob of black glue on top so there are no markings and
the 258a vendor-id used is unknown anywhere. But the keyboard has the
exact same hotkeys mapped to Fn+F1 - F10 as the other ITE8595 keyboard
I have *and* it has the same quirky behavior wrt the rfkill hotkey.

Either way as said this keyboard has the same quirk for its rfkill /
airplane mode hotkey as the ITE 8595 chip, it only sends a single release
event when pressed and released, it never sends a press event.

This commit adds the 258a:6a88 USB id to the hid-ite id-table, fixing
the rfkill key not working on this keyboard.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>