Fix build for x32

Upstream-Status: Pending
Signed-off-by: Christopher Larson <chris_larson@mentor.com>

--- lttng-tools-2.6.0/src/bin/lttng/utils.c~	2015-01-26 18:17:15.000000000 +0100
+++ lttng-tools-2.6.0/src/bin/lttng/utils.c	2015-07-30 19:45:25.632045712 +0200
@@ -130,7 +130,7 @@
 #define HAS_FLS_U32
 #endif
 
-#if defined(__x86_64)
+#if defined(__x86_64) && !defined(__ILP32__)
 static inline
 unsigned int fls_u64(uint64_t x)
 {