irqchip/qcom-pdc: Add 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.

Co-developed-by: Stephen Boyd <swboyd@chromium.org>

Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/1573855915-9841-5-git-send-email-ilina@codeaurora.org