greybus: audio: fix uninitialized variable errors found by cppcheck

Currently, if info is null, the dev_err message is dereferencing an
uninitialized module pointer.  Instead, it should use codec->dev pointer
in dev_err call and better align with other err msg in this function.

Also, ret variable might be used uninitialized in a specific case.
Avoid using it this way.

Found using static analysis with cppcheck:
Checking drivers/staging/greybus/audio_topology.c...
[drivers/staging/greybus/audio_topology.c:175]: (error) Uninitialized
variable: module
[drivers/staging/greybus/audio_topology.c:495]: (error) Uninitialized
variable: ret
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Vaibhav Agarwal <vaibhav.sr@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/audio_topology.c

@@ -172,7 +172,7 @@ static int gbcodec_mixer_ctl_info(struct snd_kcontrol *kcontrol,
 	info = (struct gb_audio_ctl_elem_info *)data->info;
 
 	if (!info) {
-		dev_err(module->dev, "NULL info for %s\n", uinfo->id.name);
+		dev_err(codec->dev, "NULL info for %s\n", uinfo->id.name);
 		return -EINVAL;
 	}
 
@@ -489,10 +489,11 @@ static int gbcodec_mixer_dapm_ctl_put(struct snd_kcontrol *kcontrol,
 			dev_err_ratelimited(codec->dev,
 					    "%d:Error in %s for %s\n", ret,
 					    __func__, kcontrol->id.name);
+			return ret;
 		}
 	}
 
-	return ret;
+	return 0;
 }
 
 #define SOC_DAPM_MIXER_GB(xname, kcount, data) \