ASoC: rsnd: care default case on rsnd_ssiu_busif_err_status_clear()

commit cfb7b8bf ("ASoC: rsnd: tidyup
rsnd_ssiu_busif_err_status_clear()") merged duplicate code, but it didn't
care about default case, and causes smatch warnings.

smatch warnings:
sound/soc/sh/rcar/ssiu.c:112 rsnd_ssiu_busif_err_status_clear() \
	error: uninitialized symbol 'offset'.
sound/soc/sh/rcar/ssiu.c:114 rsnd_ssiu_busif_err_status_clear() \
	error: uninitialized symbol 'shift'.

This patch cares it.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87r15rgn6p.wl-kuninori.morimoto.gx@renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sh/rcar/ssiu.c

@@ -102,6 +102,8 @@ bool rsnd_ssiu_busif_err_status_clear(struct rsnd_mod *mod)
 		shift  = 1;
 		offset = 1;
 		break;
+	default:
+		goto out;
 	}
 
 	for (i = 0; i < 4; i++) {
@@ -120,7 +122,7 @@ bool rsnd_ssiu_busif_err_status_clear(struct rsnd_mod *mod)
 		}
 		rsnd_mod_write(mod, reg, val);
 	}
-
+out:
 	return error;
 }