Merge pull request intel#20 from jsakkine-intel/master

Declare MAX_CALLS as const

Author: hackermnementh

lib/source/cmac_mode.c

@@ -36,7 +36,7 @@
 #include <tinycrypt/utils.h>
 
 /* max number of calls until change the key (2^48).*/
-static uint64_t MAX_CALLS = ((uint64_t)1 << 48);
+const static uint64_t MAX_CALLS = ((uint64_t)1 << 48);
 
 /*
  *  gf_wrap -- In our implementation, GF(2^128) is represented as a 16 byte