ecc: Clean up for decoding point.
* cipher/ecc-curves.c (point_from_keyparam): Possibly supporting Montgomery curve, use _gcry_mpi_ec_decode_point. (_gcry_ecc_set_mpi): Likewise. * cipher/ecc.c (ecc_check_secret_key): Likewise.
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>