Add static internal MAC finish function

add new psa_mac_finish_internal() to be called by psa_mac_finish() and
psa_mac_verify() in order to be able to check key usage separatly.
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 687a349..e8bea07 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -491,10 +491,6 @@
 /** \brief Encoding of permitted usage on a key. */
 typedef uint32_t psa_key_usage_t;
 
-/** An invalid key usage value.
- * */
-#define PSA_KEY_USAGE_NONE                      ((psa_key_usage_t)0x00000000)
-
 /** Whether the key may be exported.
  *
  * A public key or the public part of a key pair may always be exported
diff --git a/include/psa/crypto_struct.h b/include/psa/crypto_struct.h
index 8987840..eba4862 100644
--- a/include/psa/crypto_struct.h
+++ b/include/psa/crypto_struct.h
@@ -82,6 +82,8 @@
     int iv_required : 1;
     int iv_set : 1;
     int has_input : 1;
+    int key_usage_sign : 1;
+    int key_usage_verify : 1;
     uint8_t mac_size;
     union
     {