pci: Put non-prefetchable 64bit BARs into 32bit MMIO window

At the moment 64bit non-prefetchable BARs of devices behind PCI p2p
bridge go to a 64bit prefetchable windows which is not correct and
causes linux guests to fail to ioremap() such resources.

This moves 64bit non-prefetchable BARs 32bit non-prefetchable window.

Note that this does not make distinction between P2P and PHB so
from now on XHCI BARs will be allocated from 32bit MMIO space.
However since most 64bit-MMIO-capable devices have prefetchable BARs,
and XHCI BAR is just 4K (so it is unlikely to cause any space problems),
this should not affect usual behavior.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Tested-by: Laurent Vivier <lvivier@redhat.com>
---

This fixes QEMU's XHCI when it is put on a P2P PCI bridge.

There is a little naming confusion as it may look like the patch
is changing assignment for all 64bit BAR but it does not as:
- "mmio" is used for non-prefetchable memory,
- "mem" is used for prefetchable memory.

slof/fs/pci-properties.fs

@@ -166,11 +166,7 @@
 \ Setup a non-prefetchable 64bit BAR and return its size
 : assign-mmio64-bar ( bar-addr -- 8 )
         dup pci-bar-size-mem64          \ fetch size
-        pci-next-mem64 @ 0 = IF          \ Check if we have 64-bit memory range
-	    pci-next-mmio
-	ELSE
-	    pci-next-mem64              \ for board-qemu we will use same range
-	THEN
+        pci-next-mmio
         assign-bar-value64              \ and set it all
 ;