net: dsa: tag_sja1105: Slightly improve the Xmas tree in sja1105_xmit

This is a cosmetic patch that makes the dp, tx_vid, queue_mapping and
pcp local variable definitions a bit closer in length, so they don't
look like an eyesore as much.

The 'ds' variable is not used otherwise, except for ds->dp.

Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>