This patch is from Brian King <brking@us.ibm.com>.

When working with a PCI-X Mode 2 adapter on a PCI-X Mode 1 PPC64 system, the
current code used to determine the config space size of a device results in a
PCI Master abort and an EEH error, resulting in the device being taken
offline.  This patch checks OF to see if the PCI bridge supports PCI-X Mode 2
and fails config accesses beyond 256 bytes if it does not.
Signed-off-by: Brian King <brking@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>