staging: vt6656: BBvUpdatePreEDThreshold change byBBPreEDIndex

assign pDevice->byBBPreEDIndex to ed_idx and change ed_inx
value in switch.

If ed_inx == byBBPreEDIndex and not bScanning return out.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>