Comment # 6 on bug 1188327 from Takashi Iwai

FWIW, ecc_swap_digits() handles the u64 array, so copying would be needed there
instead of the caller.  (And there are two calls of ecc_swap_digits() in 
ecdsa_set_pub_key()).

If performance matters, we'd need two versions of ecc_swap_digits() for aligned
and unaligned.  But all calls of ecc_swap_digits() in ecdsa.c look suspicious
wrt alignment.