pata_sil680: kill bogus reset code (take 2)

Since writing to two reserved bits ain't much of a housekeeping, I think it's
time we get rid of the custom error handler in this driver. ;-)

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>