Revert "x86/PCI: Don't alloc pcibios-irq when MSI is enabled"

Revert 8affb487 ("x86/PCI: Don't alloc pcibios-irq when MSI is
enabled").

This is part of reverting 991de2e5 ("PCI, x86: Implement
pcibios_alloc_irq() and pcibios_free_irq()") to fix regressions it
introduced.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=111211


Fixes: 991de2e5 ("PCI, x86: Implement pcibios_alloc_irq() and pcibios_free_irq()")
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
CC: Jiang Liu <jiang.liu@linux.intel.com>
CC: Joerg Roedel <jroedel@suse.de>