staging: r8188eu: fix missing unlock in rtw_resume()

Add the missing unlock before return from rtw_resume().

Fixes: 2b42bd58 ("staging: r8188eu: introduce new os_dep dir for RTL8188eu driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Acked-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20211028094038.2877341-1-yangyingliang@huawei.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>