genirq/irqdomain: Remove the param count restriction from select()

Now that the GIC-v3 callback can handle invocation with a fwspec parameter
count of 0 lift the restriction in the core code and invoke select()
unconditionally when the domain provides it.

Preparatory change for per device MSI domains.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240127161753.114685-3-apatel@ventanamicro.com