[PATCH] ia64: don't udelay() in sn_mmiob

sn_mmiob is a lightweight way to ensure PCI write ordering, intended
to be used as an alternative to doing a PIO read. Unfortunately, with
the udelay() in there, it ends up being slower than a PCI read on
small configurations, so remove it in favor of a simple cpu_relax().

arch/ia64/sn/io/machvec/iomv.c

@@ -71,6 +71,6 @@ sn_mmiob (void)
 {
 	while ((((volatile unsigned long) (*pda->pio_write_status_addr)) & SH_PIO_WRITE_STATUS_0_PENDING_WRITE_COUNT_MASK) != 
 				SH_PIO_WRITE_STATUS_0_PENDING_WRITE_COUNT_MASK)
-		udelay(1);
+		cpu_relax();
 }
 EXPORT_SYMBOL(sn_mmiob);