Seccomp_bpf. Fix compilation error for Android x64.

There is no old version of bionic for x64.

BUG=346626

Review URL: https://codereview.chromium.org/335623002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@276817 0039d316-1c4b-4281-b951-d872f2087c98

sandbox/linux/seccomp-bpf/linux_seccomp.h

@@ -19,7 +19,7 @@
 // Old Bionic versions do not have sys/user.h.  The if can be removed once we no
 // longer need to support these old Bionic versions.
 #include <sys/cdefs.h>
-#if !defined(__BIONIC__)
+#if !defined(__BIONIC__) || defined(__x86_64__)
 #include <sys/user.h>
 #endif