staging: vt6656: vnt_get_rtscts_rsvtime_le replace with rts/cts duration.

staging: vt6656: vnt_get_rtscts_rsvtime_le replace with rts/cts duration.

rsvtime is the time needed in firmware to process the received
frame time in firmware so they can be the same as vnt_get_rts_duration
or vnt_get_cts_duration where appropriate.

The rts_rrv_time are now all the same timing in vnt_rxtx_rts.

So vnt_get_rtscts_rsvtime_le and and vnt_get_frame_time are no longer
required.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/4c0fe356-7e08-bf66-58b7-5ab683ba9536@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>