[PATCH] incomplete asm constraints in arch/i386/pci/pcbios.c

This fixes a "miscompile" HP reported against gcc 3.3 with
-march-pentium4.  It turned out to be a non-complete asm contraint.  the
existing constraint on "opt" was on the address of "opt", which allowed
gcc to reorder the setting of the fields inside opt to beyond the asm
that uses it, which is less than useful at best.

arch/i386/pci/pcbios.c

@@ -430,7 +430,8 @@ struct irq_routing_table * __devinit pcibios_get_irq_routing_table(void)
 		"xor %%ah, %%ah\n"
 		"1:"
 		: "=a" (ret),
-		  "=b" (map)
+		  "=b" (map),
+		  "+m" (opt)
 		: "0" (PCIBIOS_GET_ROUTING_OPTIONS),
 		  "1" (0),
 		  "D" ((long) &opt),