irqdomain: Add support for generic irq chips creation before publishing a domain

The current API functions create an irq_domain and also publish this
newly created to domain. Once an irq_domain is published, consumers can
request IRQ in order to use them.

Some interrupt controller drivers have to perform some more operations
with the created irq_domain in order to have it ready to be used.
For instance:
   - Allocate generic irq chips with irq_alloc_domain_generic_chips()
   - Retrieve the generic irq chips with irq_get_domain_generic_chip()
   - Initialize retrieved chips: set register base address and offsets,
     set several hooks such as irq_mask, irq_unmask, ...

With the newly introduced irq_domain_alloc_generic_chips(), an interrupt
controller driver can use the irq_domain_chip_generic_info structure and
set the init() hook to perform its generic chips initialization.

In order to avoid a window where the domain is published but not yet
ready to be used, handle the generic chip creation (i.e the
irq_domain_alloc_generic_chips() call) before the domain is published.

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/20240614173232.1184015-16-herve.codina@bootlin.com

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