ecp: rm obsolete doc about alt implementations

Signed-off-by: Manuel Pégourié-Gonnard <[email protected]>

include/mbedtls/ecp.h

@@ -218,17 +218,6 @@ mbedtls_ecp_point;
  * non-zero limbs than P, so that it may be efficiently brought into the range
  * [0, P) by a single constant-time conditional subtraction.
  * It must return 0 on success and non-zero on failure.
- *
- * \note        Alternative implementations of the ECP module must obey the
- *              following constraints.
- *              * Group IDs must be distinct: if two group structures have
- *                the same ID, then they must be identical.
- *              * The fields \c id, \c P, \c A, \c B, \c G, \c N,
- *                \c pbits and \c nbits must have the same type and semantics
- *                as in the built-in implementation.
- *                They must be available for reading, but direct modification
- *                of these fields does not need to be supported.
- *                They do not need to be at the same offset in the structure.
  */
 typedef struct mbedtls_ecp_group {
     mbedtls_ecp_group_id id;    /*!< An internal group identifier. */