ieee1394: hpsb_send_phy_config() cleanup

Eliminate some code in hpsb_send_phy_config() which is provided
by hpsb_make_phypacket().

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jody McIntyre <scjody@modernduck.com>