powerpc/eeh: remove unused macro IS_BRIDGE

Currently, the macro IS_BRIDGE is not used any where.
This patch just removes it.
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/eeh.c

@@ -144,8 +144,6 @@ struct eeh_stats {
 
 static struct eeh_stats eeh_stats;
 
-#define IS_BRIDGE(class_code) (((class_code)<<16) == PCI_BASE_CLASS_BRIDGE)
-
 static int __init eeh_setup(char *str)
 {
 	if (!strcmp(str, "off"))