genirq/irqdomain: Remove unused irq_domain_check_msi_remap() code

After converting the users of irq_domain_check_msi_remap() it and the
helpers are no longer needed.

The new version does not require all the #ifdef helpers and inlines
because CONFIG_GENERIC_MSI_IRQ always requires CONFIG_IRQ_DOMAIN and
IRQ_DOMAIN_HIERARCHY.

Link: https://lore.kernel.org/r/5-v3-3313bb5dd3a3+10f11-secure_msi_jgg@nvidia.com


Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>