Interface: Add necessary include in tfm_ns_lock.h

tfm_ns_lock.h uses enum tfm_status_e defined in tfm_api.h

Change-Id: Ice90f59f79603659b863303ae7b33f1913640fc7
diff --git a/interface/include/tfm_ns_lock.h b/interface/include/tfm_ns_lock.h
index d3cf055..d9acd00 100644
--- a/interface/include/tfm_ns_lock.h
+++ b/interface/include/tfm_ns_lock.h
@@ -12,6 +12,7 @@
 #endif
 
 #include <stdint.h>
+#include "tfm_api.h"
 
 typedef int32_t (*veneer_fn) (uint32_t arg0, uint32_t arg1,
                       uint32_t arg2, uint32_t arg3);