irqdomain: Introduce irq_domain_free()

irqdomain: Introduce irq_domain_free()

In preparation of the introduction of the irq domain instantiation,
introduce irq_domain_free() to avoid code duplication on later
modifications.

This new function is an extraction of the current operations performed
to free the irq domain. No functional change intended.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240614173232.1184015-2-herve.codina@bootlin.com