UPSTREAM: irqdomain: Introduce is_fwnode_irqchip helper

UPSTREAM: irqdomain: Introduce is_fwnode_irqchip helper

Since there will be several places checking if fwnode.type
is equal FWNODE_IRQCHIP, this patch adds a convenient function
for this purpose.

Change-Id: I65ab9e1350428de18864ba493256b959efc01f45
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
(cherry picked from commit 75aba7b0e9ac416ca53c0c97680b8e9aedf09284)