staging: vt6655: Fix loss of distant/weak access points on channel change.

If the asssocated access point is strong byBBVGACurrent will be adjusted
accordingly.

Users will nolonger see distant access points without taking down interface.

When changing channel reset byBBVGACurrent back to pDevice->abyBBVGA[0] for
max sensitivity.

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