irqchip: Provide irq-msi-lib

irqchip: Provide irq-msi-lib

All irqdomains which provide MSI parent domain functionality for per device
MSI domains need to provide a select() callback for the irqdomain and a
function to initialize the child domain.

Most of these functions would just be copy&paste with minimal
modifications, so provide a library function which implements the required
functionality and is customizable via parent_domain::msi_parent_ops. The
check for the supported bus tokens in msi_lib_init_dev_msi_info() is
expanded step by step within the next patches.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Shivamurthy Shastri <shivamurthy.shastri@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240623142234.840975799@linutronix.de