ALSA: Close holes in struct snd_pcm_constraint_list

On a 64-bit system there is a 32-bit hole in struct snd_pcm_constraint_list
and then 32-bit padding at the end. Reordering things slightly gets rid of
the hole and padding, reducing the size of the struct by 50% from its
original size.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>