acme-client: use field agnostic {get,set}_affine_coordinates()

[Theo Buehler]

The _GFp() variants provide no benefit and are just wrappers around the
variants without _GFp(), so use the latter directly.

Index: acctproc.c
===================================================================
RCS file: /cvs/src/usr.sbin/acme-client/acctproc.c,v
retrieving revision 1.20
diff -u -p -r1.20 acctproc.c
--- acctproc.c  17 Jun 2019 15:20:10 -0000      1.20
+++ acctproc.c  13 May 2021 05:38:59 -0000
@@ -109,9 +109,9 @@ op_thumb_ec(EVP_PKEY *pkey)
                warnx("BN_new");
        else if ((Y = BN_new()) == NULL)
                warnx("BN_new");
-       else if (!EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(ec),
+       else if (!EC_POINT_get_affine_coordinates(EC_KEY_get0_group(ec),
            EC_KEY_get0_public_key(ec), X, Y, NULL))
-               warnx("EC_POINT_get_affine_coordinates_GFp");
+               warnx("EC_POINT_get_affine_coordinates");
        else if ((x = bn2string(X)) == NULL)
                warnx("bn2string");
        else if ((y = bn2string(Y)) == NULL)
@@ -237,9 +237,9 @@ op_sign_ec(char **prot, EVP_PKEY *pkey, 
                warnx("BN_new");
        else if ((Y = BN_new()) == NULL)
                warnx("BN_new");
-       else if (!EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(ec),
+       else if (!EC_POINT_get_affine_coordinates(EC_KEY_get0_group(ec),
            EC_KEY_get0_public_key(ec), X, Y, NULL))
-               warnx("EC_POINT_get_affine_coordinates_GFp");
+               warnx("EC_POINT_get_affine_coordinates");
        else if ((x = bn2string(X)) == NULL)
                warnx("bn2string");
        else if ((y = bn2string(Y)) == NULL)