[IA64] Require SAL 3.2 in order to do extended config space ops

We had assumed that SAL firmware would return an error if it didn't
understand extended config space.  Unfortunately, the SAL on the SGI 750
doesn't do that, it panics the machine.  So, condition the extended PCI
config space accesses on SAL revision 3.2.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Tony Luck <tony.luck@intel.com>