fix sn2 pci discovery in generic kernels

Don't try to use the sn2 I/O code if we're not on sn2 or we may get into trouble. Only makes a difference for generic kernels.

Thanks,
Jesse

=== arch/ia64/sn/io/machvec/pci_bus_cvlink.c 1.10 vs edited ==--- 1.10/arch/ia64/sn/io/machvec/pci_bus_cvlink.c Mon Sep 8 05:12:36 2003
+++ edited/arch/ia64/sn/io/machvec/pci_bus_cvlink.c Tue Oct 7 11:39:30 2003
@@ -863,6 +863,9 @@
int i = 0;
struct pci_controller *controller;

+ if (!ia64_platform_is("sn2"))
+ return 0;
+
/*
* set pci_raw_ops, etc.
*/