ALSA: Close holes in struct snd_pcm_hw_rule

On a 64-bit system there are two 32-bit holes due to the alignment of 64-bit
fields. Reordering things slightly gets rid of those holes, reducing the
size of the struct by 17% percent of its original size.

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