This patch adds pci_get_legacy_ide_irq() to the PCI layer for dealing
with PCI IDE chipsets that use the "legacy mode" IRQ routing, thus
violating the normal PCI routing.  The generic implementation provides
IRQ numbers 14 and 15, and it adds a ppc64 specific one with platform
callbacks so that a plaform can provide different IRQ numbers for "legacy"
IDE.  I only fixed the amd7xxx.c driver for now, I expect people using
this interface will slowly fix their drivers (I will fix via soon as I'll
need it too, and maybe a few others).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>