staging: vt6656: s_uCalculateLinkQual use netstats rx values

Use netstats rx_packets and rx_frame_errors.

Add frame errors to RXbBulkInProcessData

The current scStatistic.RxFcsErrCnt only records
USB errors not frame errors.

The scStatistic.RxOkCnt only recorded successful USB
transfers not actual successfully received packets.

So a more accurate reading is to use netstats rx_packets and
rx_frame_errors.

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