staging: rtl8723bs: remove VHT dead code

remove VHT dead code, as the device doesn't support
VHT (which is a 802.11ac capability).

Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/2ca4be24e401bd862a96e2641a9b0377be36a25d.1624367072.git.fabioaiuto83@gmail.com


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