staging: greybus: audio: Uninitialized variable in gbaudio_remove_controls()

The "err" variable is not meaningful so there is no need to print it.
It's uninitialized on the first iteration through the loop.

Fixes: 510e340e ("staging: greybus: audio: Add helper APIs for dynamic audio modules")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Reviewed-by: Vaibhav Agarwal <vaibhav.sr@gmail.com>
Link: https://lore.kernel.org/r/20200804101601.GA392148@mwandaSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/audio_helper.c

@@ -173,8 +173,7 @@ static int gbaudio_remove_controls(struct snd_card *card, struct device *dev,
 		id.index = control->index;
 		kctl = snd_ctl_find_id(card, &id);
 		if (!kctl) {
-			dev_err(dev, "%d: Failed to find %s\n", err,
-				control->name);
+			dev_err(dev, "Failed to find %s\n", control->name);
 			continue;
 		}
 		err = snd_ctl_remove(card, kctl);