ALSA: hda/ca0132: Use const char * for strings

ALSA: hda/ca0132: Use const char * for strings

Some static strings have been stored in fixed char arrays although
they could be gracefully "const char *" instead.  Also, a few other
definitions use the raw "char *" without const.

Converting those to "const char *" will save some memory and give more
safety, in addition to a side-effect to address the bogus compiler
warning with snprintf().

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202506121025.G9uunMlx-lkp@intel.com/
Link: https://patch.msgid.link/20250612064802.1170-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>