x86/msi: Consolidate MSI allocation

Convert the interrupt remap drivers to retrieve the pci device from the msi
descriptor and use info::hwirq.

This is the first step to prepare x86 for using the generic MSI domain ops.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20200826112332.466405395@linutronix.de