ASoC: smd845: constify snd_soc_ops structure

The snd_soc_ops structure can be const as it is only stored in the
ops field of a snd_soc_dai_link structure and this field is const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>