staging: rtl8188eu: Remove inline function rtw_inc_and_chk_continual_urb_error()

rtw_inc_and_chk_continual_urb_error() is used to check if device is
removed unexpectedly, to do that we can just check status of urb in
usb_read_port_complete() and usbctrl_vendorreq() doed that by checking
return value of usb_control_msg().

Signed-off-by: navin patidar <navin.patidar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>