wifi: brcmfmac: of: Support interrupts-extended

The currently existing of_property_present check for interrupts does not
cover all ways interrupts can be defined in a device tree, e.g.
"interrupts-extended".

In order to support all current and future ways that can be done, drop that
check and call of_irq_parse_one to figure out if an interrupt is defined
and irq_create_of_mapping for the actual mapping and let it be handled by
the interrupt subsystem.

Signed-off-by: Alex Bee <knaerzche@gmail.com>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20240622215416.659208-1-knaerzche@gmail.com