bridge: use an explicit chip select.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
bridge: use a registered write enable.

We need the write enable to stay stable over both writes so keep it
registered locally.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
bridge: lower bytesel as soon as complete.

The SDRAM controller uses bytesel != 0 as a chip select so we need to
take it low as soon as the transaction is complete so we don't start a
new, erroneous transaction.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
controller: remove explicit counter include.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>