[PATCH] Change #if CONFIG_6xx -> #if defined(CONFIG_6xx) in perfmon.c

[Roland Dreier]

This trivial change fixes the warning

    arch/ppc/kernel/perfmon.c:48:7: warning: "CONFIG_6xx" is not defined

Signed-off-by: Roland Dreier <rolandd at cisco.com>

diff --git a/arch/ppc/kernel/perfmon.c b/arch/ppc/kernel/perfmon.c
--- a/arch/ppc/kernel/perfmon.c
+++ b/arch/ppc/kernel/perfmon.c
@@ -45,7 +45,7 @@ static void dummy_perf(struct pt_regs *r
 	mtpmr(PMRN_PMGC0, pmgc0);
 }
 
-#elif CONFIG_6xx
+#elif defined (CONFIG_6xx)
 /* Ensure exceptions are disabled */
 
 static void dummy_perf(struct pt_regs *regs)