drivers: irqchip: add PDC irqdomain for wakeup capable GPIOs

Introduce a new domain for wakeup capable GPIOs. The domain can be
requested using the bus token DOMAIN_BUS_WAKEUP. In the following
patches, we will specify PDC as the wakeup-parent for the TLMM GPIO
irqchip. Requesting a wakeup GPIO will setup the GPIO and the
corresponding PDC interrupt as its parent.

Change-Id: I13b206773e5f04452eed87ad1490da50b034ac4c
Co-developed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Lina Iyer <ilina@codeaurora.org>