Add new global mutex for PSA global_data

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/library/threading.c b/library/threading.c
index c28290f..06b4747 100644
--- a/library/threading.c
+++ b/library/threading.c
@@ -150,6 +150,7 @@
 #endif
 #if defined(MBEDTLS_PSA_CRYPTO_C)
     mbedtls_mutex_init(&mbedtls_threading_key_slot_mutex);
+    mbedtls_mutex_init(&mbedtls_threading_psa_globaldata_mutex);
 #endif
 }
 
@@ -166,6 +167,7 @@
 #endif
 #if defined(MBEDTLS_PSA_CRYPTO_C)
     mbedtls_mutex_free(&mbedtls_threading_key_slot_mutex);
+    mbedtls_mutex_free(&mbedtls_threading_psa_globaldata_mutex);
 #endif
 }
 #endif /* MBEDTLS_THREADING_ALT */
@@ -184,6 +186,7 @@
 #endif
 #if defined(MBEDTLS_PSA_CRYPTO_C)
 mbedtls_threading_mutex_t mbedtls_threading_key_slot_mutex MUTEX_INIT;
+mbedtls_threading_mutex_t mbedtls_threading_psa_globaldata_mutex MUTEX_INIT;
 #endif
 
 #endif /* MBEDTLS_THREADING_C */