greybus: interface: delete control device upon enable failure

There is an issue that when an interface failed to be enabled due to
timesync failure, a previously added control device is not deleted as
part of the error clean-up. This causes a leak in the sysfs file when
the interface is disabled. This would eventually cause this particular
interface to be unable to register future control device even after
unipro_reset. See failure logs below:

[  906.495261] greybus 1-3.3: failed to add to timesync: -19
[  906.516497] greybus 1-3.3: failed to re-enable interface: -19
[  907.016016] greybus 1-3.3: Interface removed
...
[ 1623.677343] ------------[ cut here ]------------
[ 1623.681116] WARNING: at kernel/arche/fs/sysfs/dir.c:530 sysfs_add_one+0x98/0xb4()
[ 1623.681128] sysfs: cannot create duplicate filename '/bus/greybus/devices/1-3.3.ctrl'
[ 1623.681252] Call trace:
[ 1623.681265] [<ffffffc000207b40>] dump_backtrace+0x0/0x268
[ 1623.681272] [<ffffffc000207db8>] show_stack+0x10/0x1c
[ 1623.681284] [<ffffffc000ccb890>] dump_stack+0x1c/0x28
[ 1623.681295] [<ffffffc00021f9dc>] warn_slowpath_common+0x74/0x9c
[ 1623.681301] [<ffffffc00021fa60>] warn_slowpath_fmt+0x5c/0x80
[ 1623.681307] [<ffffffc000366624>] sysfs_add_one+0x94/0xb4
[ 1623.681315] [<ffffffc0003670b4>] sysfs_do_create_link_sd+0x100/0x1c8
[ 1623.681320] [<ffffffc0003671a8>] sysfs_create_link+0x2c/0x38
[ 1623.681332] [<ffffffc0005d5890>] bus_add_device+0xd8/0x190
[ 1623.681338] [<ffffffc0005d39ec>] device_add+0x2b4/0x604
[ 1623.681349] [<ffffffbffc006dfc>] gb_control_add+0x10/0x40 [greybus]
[ 1623.681362] [<ffffffbffc003dac>] gb_interface_enable+0x20c/0x3b8 [greybus]
[ 1623.681373] [<ffffffbffc002a30>] gb_module_add+0x124/0x174 [greybus]
[ 1623.681385] [<ffffffbffc0082cc>] gb_svc_intf_set_power_mode+0xdd4/0xfe8 [greybus]
[ 1623.681394] [<ffffffc00023888c>] process_one_work+0x268/0x3c8
[ 1623.681400] [<ffffffc000239a64>] worker_thread+0x204/0x358
[ 1623.681410] [<ffffffc00023f43c>] kthread+0xb8/0xc4
[ 1623.681414] ---[ end trace 44489577dd9220db ]---
[ 1623.681818] greybus 1-3.3.ctrl: failed to register control device: -17

Testing Done:
 - Continuous unipro_reset stress test

Signed-off-by: David Lin <dtwlin@google.com>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Jeffrey Carlyle <jcarlyle@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/interface.c

@@ -1160,7 +1160,7 @@ int gb_interface_enable(struct gb_interface *intf)
 	ret = gb_timesync_interface_add(intf);
 	if (ret) {
 		dev_err(&intf->dev, "failed to add to timesync: %d\n", ret);
-		goto err_destroy_bundles;
+		goto err_del_control;
 	}
 
 	pm_runtime_use_autosuspend(&intf->dev);
@@ -1186,6 +1186,8 @@ int gb_interface_enable(struct gb_interface *intf)
 
 	return 0;
 
+err_del_control:
+	gb_control_del(intf->control);
 err_destroy_bundles:
 	list_for_each_entry_safe(bundle, tmp, &intf->bundles, links)
 		gb_bundle_destroy(bundle);