Update PCIe Root Port _PRT to handle re-mapped functions

The chipset enforces static-defined interrupt swizzling on PCIe root
ports so if a port is remapped to a different function it needs to
still report the proper interrupt map to the OS instead of assuming
that function number is equivalent to root port number.

This change also includes an update to the PCH function disable
register which was incorrect for CPT/PPT and would cause unpredictable
behavior if used.

The kernel command line was changed to add 'nomsi' in order to force
PCIe devices to use IO-APIC assigned interrupts and not MSI to ensure
that the mapping is correct.

LUMPY current:

  00:1c.0 PCI bridge: Intel Corporation Device 1c10 (rev b5)
  00:1c.3 PCI bridge: Intel Corporation Device 1c16 (rev b5)

  16:   41518   0   0   0   IO-APIC-fasteoi   i915, ahci, ath9k
  19:     720   0   0   0   IO-APIC-fasteoi   ehci_hcd:usb2, eth0

LUMPY with PCIe port coalesce enabled:

  00:1c.0 PCI bridge: Intel Corporation Device 1c10 (rev b5)
  00:1c.1 PCI bridge: Intel Corporation Device 1c16 (rev b5)

  16:   38988   0   0   0   IO-APIC-fasteoi   i915, ahci, ath9k
  19:     347   0   0   0   IO-APIC-fasteoi   ehci_hcd:usb2, eth0

Change-Id: Ia5f6bb8888b5c38a5dbc88bb25ecdf1fca41ee3e
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/978
Tested-by: build bot (Jenkins)
3 files changed