audit: support the "standard" <asm-generic/unistd.h>

Many of the syscalls mentioned in the audit code are not present
for architectures that implement only the "standard" set of
Linux syscalls (e.g. openat, but not open, etc.).  This change
adds proper #ifdefs for all those syscalls.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

include/asm-generic/audit_read.h

@@ -1,4 +1,6 @@
+#ifdef __NR_readlink
 __NR_readlink,
+#endif
 __NR_quotactl,
 __NR_listxattr,
 __NR_llistxattr,
@@ -6,3 +8,6 @@ __NR_flistxattr,
 __NR_getxattr,
 __NR_lgetxattr,
 __NR_fgetxattr,
+#ifdef __NR_readlinkat
+__NR_readlinkat,
+#endif