staging: wilc1000: fix static checker warning to unlock mutex in wilc_deinit()

staging: wilc1000: fix static checker warning to unlock mutex in wilc_deinit()

Fix for static checker warning inconsistent returns of
'hif_deinit_lock'(more details [1]).

"drivers/staging/wilc1000/host_interface.c:3390 wilc_deinit()
              warn: inconsistent returns 'hif_deinit_lock'."

Fixes: ff52a57a7a42 ("staging: wilc1000: move the allocation of cmd out
of wilc_enqueue_cmd()")

[1]. https://www.spinics.net/lists/linux-driver-devel/msg114216.html

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>