Disabling SCSI parity checking

In trying to fix bug #2236 I came across this little gem:

        /* If any device does not support parity, we will not use this option */
        if (!(tn->flags & TEKRAM_PARITY_CHECK))
                np->rv_scntl0  &= ~0x0a; /* SCSI parity checking disabled */

I'm pretty fundamentally opposed to disabling parity checking, so I'm going to delete this code. However, I've taken flack before (oh yes, in bug 2236 ;-) for "not honouring the controller's own setup", so I thought I'd let people know in advance that I'm going to take away this option.

It would be possible to put it back if it really hurts people.