Add missing #include.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@4070 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/cachegrind/cg-amd64.c b/cachegrind/cg-amd64.c
index 4add1a6..0ac02bf 100644
--- a/cachegrind/cg-amd64.c
+++ b/cachegrind/cg-amd64.c
@@ -29,6 +29,7 @@
 */
 
 #include "pub_tool_basics.h"
+#include "pub_tool_cpuid.h"
 #include "pub_tool_libcbase.h"
 #include "pub_tool_libcassert.h"
 #include "pub_tool_libcprint.h"