* cipher/ecc-curves.c (_gcry_ecc_fill_in_curve): Don't use mpi_add
since it resizes to have more limbs.
* mpi/ec.c (point_resize): Fix for Edwards curve.
(ec_p_init): Support Edwards curve.
(_gcry_mpi_ec_get_affine): Use the methods.
(dup_point_edwards, add_points_edwards, sub_points_edwards): Ditto.
(_gcry_mpi_ec_mul_point): Resize MPIs of point to fixed size.
(_gcry_mpi_ec_curve_point): Use the methods.