staging: wfx: fix warning when unregister a frozen device

staging: wfx: fix warning when unregister a frozen device

The device does not answer to the command hif_shutdown. Therefore,
hif_shutdown() is a bit special. It bypasses some of work normally made
by wfx_cmd_send(). In particularly, it unlock hif_cmd.lock and
hif_cmd.key_renew_lock.

However, if the driver notice that the device is frozen, wfx_cmd_send()
stops to send data and doesn't lock the mutexes. Then, it produced a
warning when hif_shutdown() tried to unlock these mutexes.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200515083325.378539-2-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>