staging: rtl8712: fix a potential memory leak in r871xu_drv_init()

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8712: fix a potential memory leak in r871xu_drv_init() In r871xu_drv_init(), if r8712_init_drv_sw() fails, then the memory allocated by r8712_alloc_io_queue() in r8712_usb_dvobj_init() is not properly released as there is no action will be performed by r8712_usb_dvobj_deinit(). To properly release it, we should call r8712_free_io_queue() in r8712_usb_dvobj_deinit(). Besides, in r871xu_dev_remove(), r8712_usb_dvobj_deinit() will be called by r871x_dev_unload() under condition `padapter->bup` and r8712_free_io_queue() is called by r8712_free_drv_sw(). However, r8712_usb_dvobj_deinit() does not rely on `padapter->bup` and calling r8712_free_io_queue() in r8712_free_drv_sw() is negative for better understading the code. So I move r8712_usb_dvobj_deinit() into r871xu_dev_remove(), and remove r8712_free_io_queue() from r8712_free_drv_sw().