Guard the tinycrypt code with MBEDTLS_USE_TINYCRYPT

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/tinycrypt/ecc.c b/tinycrypt/ecc.c
index cfc527b..6c944d3 100644
--- a/tinycrypt/ecc.c
+++ b/tinycrypt/ecc.c
@@ -63,6 +63,7 @@
 #include MBEDTLS_CONFIG_FILE
 #endif
 
+#if defined(MBEDTLS_USE_TINYCRYPT)
 #include <tinycrypt/ecc.h>
 #include "mbedtls/platform_util.h"
 #include "mbedtls/sha256.h"
@@ -1853,3 +1854,4 @@
 
 	return ret;
 }
+#endif /* MBEDTLS_USE_TINYCRYPT */