staging: vt6656: [BUG] BBvUpdatePreEDThreshold Always set sensitivity on bScanning

commit 8f248dae133668bfb8e9379b4b3f0571c858b24a upstream.

byBBPreEDIndex value is initially 0, this means that from
cold BBvUpdatePreEDThreshold is never set.

This means that sensitivity may be in an ambiguous state,
failing to scan any wireless points or at least distant ones.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>