HID: intel-ish-hid: Remove unused variable 'err'

Fixes the following W=1 kernel build warning(s):

 drivers/hid/intel-ish-hid/ishtp/client.c: In function ‘ishtp_cl_disconnect’:
 drivers/hid/intel-ish-hid/ishtp/client.c:266:6: warning: variable ‘err’ set but not used [-Wunused-but-set-variable]

Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: linux-input@vger.kernel.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

drivers/hid/intel-ish-hid/ishtp/client.c

@@ -263,7 +263,6 @@ EXPORT_SYMBOL(ishtp_cl_unlink);
 int ishtp_cl_disconnect(struct ishtp_cl *cl)
 {
 	struct ishtp_device *dev;
-	int err;
 
 	if (WARN_ON(!cl || !cl->dev))
 		return -ENODEV;
@@ -283,7 +282,7 @@ int ishtp_cl_disconnect(struct ishtp_cl *cl)
 		return -ENODEV;
 	}
 
-	err = wait_event_interruptible_timeout(cl->wait_ctrl_res,
+	wait_event_interruptible_timeout(cl->wait_ctrl_res,
 			(dev->dev_state != ISHTP_DEV_ENABLED ||
 			cl->state == ISHTP_CL_DISCONNECTED),
 			ishtp_secs_to_jiffies(ISHTP_CL_CONNECT_TIMEOUT));