nios2: Switch to irq_domain_create_linear()

nios2: Switch to irq_domain_create_linear()

irq_domain_add_linear() is going away as being obsolete now. Switch to
the preferred irq_domain_create_linear(). That differs in the first
parameter: It takes more generic struct fwnode_handle instead of struct
device_node. Therefore, of_fwnode_handle() is added around the
parameter.

Note some of the users can likely use dev->fwnode directly instead of
indirect of_fwnode_handle(dev->of_node). But dev->fwnode is not
guaranteed to be set for all, so this has to be investigated on case to
case basis (by people who can actually test with the HW).

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250319092951.37667-29-jirislaby@kernel.org