Add and fix comments

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/scripts/mbedtls_dev/ecp.py b/scripts/mbedtls_dev/ecp.py
index f448925..e245171 100644
--- a/scripts/mbedtls_dev/ecp.py
+++ b/scripts/mbedtls_dev/ecp.py
@@ -147,7 +147,7 @@
 
 class EcpP256R1Raw(bignum_common.ModOperationCommon,
                    EcpTarget):
-    """Test cases for ecp quasi_reduction()."""
+    """Test cases for ECP P256 fast reduction."""
     symbol = "-"
     test_function = "ecp_mod_p256_raw"
     test_name = "ecp_mod_p256_raw"