Constifying "struct snd_soc_tplg_ops" moves some data to a read-only
section, so increase overall security.

On a x86_64, with allmodconfig:
Before:
   text	   data	    bss	    dec	    hex	filename
  58844	   5282	     56	  64182	   fab6	sound/soc/intel/skylake/skl-topology.o

After:
   text	   data	    bss	    dec	    hex	filename
  59004	   5122	     56	  64182	   fab6	sound/soc/intel/skylake/skl-topology.o
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Link: https://msgid.link/r/48f096b6dc617ecf3ca53211c2a696a4df33b21a.1715526069.git.christophe.jaillet@wanadoo.frSigned-off-by: Mark Brown <broonie@kernel.org>