fix/work around dependency issues when !MBEDTLS_ECP_C

Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>
diff --git a/include/mbedtls/debug.h b/include/mbedtls/debug.h
index 9a17488..922e5be 100644
--- a/include/mbedtls/debug.h
+++ b/include/mbedtls/debug.h
@@ -230,7 +230,7 @@
                              const char *text, const mbedtls_mpi *X);
 #endif
 
-#if defined(MBEDTLS_ECP_C)
+#if defined(MBEDTLS_ECP_LIGHT)
 /**
  * \brief   Print an ECP point to the debug output. This function is always
  *          used through the MBEDTLS_SSL_DEBUG_ECP() macro, which supplies the