staging: r8188eu: remove rtw_calculate_wlan_pkt_size_by_attribue()

Function rtw_calculate_wlan_pkt_size_by_attribue() is not used,
remove it.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210922200420.9693-47-straube.linux@gmail.com


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