ALSA: aoa: Constify struct codec_connection

ALSA: aoa: Constify struct codec_connection

'struct codec_connection' are not modified in this driver.

Constifying these structures moves some data to a read-only section, so
increases overall security.

On a x86_64, with allmodconfig:
Before:
======
   text	   data	    bss	    dec	    hex	filename
  10034	   3392	     12	  13438	   347e	sound/aoa/fabrics/layout.o

After:
=====
   text	   data	    bss	    dec	    hex	filename
  10370	   3040	     12	  13422	   346e	sound/aoa/fabrics/layout.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://patch.msgid.link/4009c337cc1a1a57795562279270c03687973b3b.1772138640.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Takashi Iwai <tiwai@suse.de>