Allow configuring an optional dedicated wakeirq for gpio-keys that
some SoCs have.

Let's use the common interrupt naming "irq" and "wakeup" that we already
have in use for some drivers and subsystems like i2c framework.

Note that the gpio-keys interrupt property is optional. If only a gpio
property is specified, the driver tries to translate the gpio into an
interrupt.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20231129110618.27551-1-tony@atomide.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>