HID: asus: Add support for the ASUS T101HA keyboard dock

The ASUS T101HA keyboard dock generates HID events using the ASUS vendor
specific UsagePage 0xff31. In consequence, some multimedia keys such as
brightness up and down are not working with hid-generic.

This commit adds the T101HA dock into the supported device list of the
hid-asus driver. It also prevents the dock's integrated touchpad to be
bound with hid-asus given that it is already working fine with
hid-multitouch.

Signed-off-by: Aleix Roca Nonell <kernelrocks@gmail.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>