HID: Wiimote: Treat the d-pad as an analogue stick

The controllers from the Super Nintendo Classic Edition (AKA the SNES
Mini) appear as a Classic Controller Pro when connected to a Wii
Remote. All the buttons work as the same, with the d-pad being mapped
the same as the d-pad on the Classic Controller Pro. This differs from
the behaviour of most controllers with d-pads and no analogue sticks,
where the d-pad maps to ABS_HAT1X for left and right, and ABS_HAT1Y
for up and down. This patch adds an option to the hid-wiimote module
to make the Super Nintendo Classic Controller behave this way.

The patch has been tested with a Super Nintendo Classic Controller
plugged into a Wii Remote in both with the option both enabled and
disabled. When enabled the d-pad acts as the analogue control, and
when disabled it acts as it did before the patch was applied. This
patch has not been tested with e Wii Classic Controller (either the
original or the pro version) as I do not have one of these
controllers.

Although I have not tested it with these controllers, I think it is
likely this patch will also work with the NES Classic Edition
Controllers.

Signed-off-by: Daniel G. Morse <dmorse@speedfox.co.uk>
Reviewed-by: David Rheinsberg <david.rheinsberg@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>