SUNRPC: Remove wrap/unwrap function pointers from enctype table

SUNRPC: Remove wrap/unwrap function pointers from enctype table

Every enctype points .wrap and .unwrap at gss_krb5_wrap_v2()
and gss_krb5_unwrap_v2(). As with get_mic/verify_mic, the
indirection dates from when v1 enctypes had different wrap
implementations. Call the functions directly and remove the
pointers from struct gss_krb5_enctype.

Assisted-by: Claude:claude-opus-4-6
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Anna Schumaker <anna.schumaker@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>