staging: r8188eu: remove to_fr_ds from struct rx_pkt_attrib

staging: r8188eu: remove to_fr_ds from struct rx_pkt_attrib

to_fr_ds in struct rx_pkt_attrib stores the values of the to_ds and
from_ds bits of an incoming data frame. to_fr_ds is set by parsing the
frame control bytes and it's used only in validate_recv_data_frame.

Remove to_fr_ds from struct rx_pkt_attrib and use the ieee80211 helpers
to distinguish between the four different cases for to_ds, from_ds.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220403165438.357728-8-martin@kaiser.cx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>