net/ncsi: Stop monitor if channel times out or is inactive

ncsi_channel_monitor() misses stopping the channel monitor in several
places that it should, causing a WARN_ON_ONCE() to trigger when the
monitor is re-started later, eg:

[  459.040000] WARNING: CPU: 0 PID: 1093 at net/ncsi/ncsi-manage.c:269 ncsi_start_channel_monitor+0x7c/0x90
[  459.040000] CPU: 0 PID: 1093 Comm: kworker/0:3 Not tainted 4.10.17-gaca2fdd #140
[  459.040000] Hardware name: ASpeed SoC
[  459.040000] Workqueue: events ncsi_dev_work
[  459.040000] [<80010094>] (unwind_backtrace) from [<8000d950>] (show_stack+0x20/0x24)
[  459.040000] [<8000d950>] (show_stack) from [<801dbf70>] (dump_stack+0x20/0x28)
[  459.040000] [<801dbf70>] (dump_stack) from [<80018d7c>] (__warn+0xe0/0x108)
[  459.040000] [<80018d7c>] (__warn) from [<80018e70>] (warn_slowpath_null+0x30/0x38)
[  459.040000] [<80018e70>] (warn_slowpath_null) from [<803f6a08>] (ncsi_start_channel_monitor+0x7c/0x90)
[  459.040000] [<803f6a08>] (ncsi_start_channel_monitor) from [<803f7664>] (ncsi_configure_channel+0xdc/0x5fc)
[  459.040000] [<803f7664>] (ncsi_configure_channel) from [<803f8160>] (ncsi_dev_work+0xac/0x474)
[  459.040000] [<803f8160>] (ncsi_dev_work) from [<8002d244>] (process_one_work+0x1e0/0x450)
[  459.040000] [<8002d244>] (process_one_work) from [<8002d510>] (worker_thread+0x5c/0x570)
[  459.040000] [<8002d510>] (worker_thread) from [<80033614>] (kthread+0x124/0x164)
[  459.040000] [<80033614>] (kthread) from [<8000a5e8>] (ret_from_fork+0x14/0x2c)

This also updates the monitor instead of just returning if
ncsi_xmit_cmd() fails to send the get-link-status command so that the
monitor properly times out.

Fixes: e6f44ed6

 "net/ncsi: Package and channel management"

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>