staging: vt6656: Split RTS and CTS Duration functions

split vnt_get_rtscts_duration_le into vnt_get_rts_duration and
vnt_get_cts_duration.

The duration's are all the same in vnt_rxtx_rts_g_head.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/d2983161-7935-48ce-c0ca-a26ebafa3997@gmail.com


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