ACPI_NUMA: fix HP IA64 simulator issue with extended memory domain

ACPI 3.0 incorporated the SRAT spec, upping the table version to 2,
and extending the size of the proximity domain from 1-byte to 4-bytes.
This extension was into a reserved field that firmware should
set to 0, but the HP simulator had non-zero values there
resulting in unexpected huge numbers.

So mask the domain down to 8-bits for now.
A more general fix will be to check the table version
supplied by firmware and get paranoid about reserved fields.
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

arch/ia64/kernel/acpi.c

@@ -422,8 +422,8 @@ static int get_memory_proximity_domain(struct acpi_srat_mem_affinity *ma)
 	int pxm;
 
 	pxm = ma->proximity_domain;
-	if (ia64_platform_is("sn2"))
-		pxm += ma->reserved << 8;
+	if (!ia64_platform_is("sn2"))
+		pxm &= 0xff;
 
 	return pxm;
 }