HID: nintendo: Fix N64 controller being identified as mouse

This patch is regarding the recent addition of support for the NSO
controllers to hid-nintendo. All controllers are working correctly with the
exception of the N64 controller, which is being identified as a mouse by
udev. This results in the joystick controlling the mouse cursor and the
controller not being detected by games.

The reason for this is because the N64's C buttons have been attributed to
BTN_FORWARD, BTN_BACK, BTN_LEFT, BTN_RIGHT, which are buttons typically
attributed to mice.

This patch changes those buttons to controller buttons, making the
controller be correctly identified as such.

Signed-off-by: Nuno Pereira <nf.pereira@outlook.pt>
Signed-off-by: Jiri Kosina <jkosina@suse.com>