dt-bindings: mfd: adp5585: add properties for input events

dt-bindings: mfd: adp5585: add properties for input events

Add properties related to input events. These devices can act as
keyboards and can support events either via a keymap Matrix or through
GPIs. Note that the device needs to be an interrupt controller for GPIs
based events.

We specifically need a property specifying the pins used by the keymap
matrix since these devices have no requirement for rows and columns to be
contiguous without holes which is enforced by the standard input
properties.

Reviewed-by: "Rob Herring (Arm)" <robh@kernel.org>
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20250701-dev-adp5589-fw-v7-11-b1fcfe9e9826@analog.com
Signed-off-by: Lee Jones <lee@kernel.org>