firewire: wait until PHY configuration packet was transmitted (fix bus reset loop)

We now exit fw_send_phy_config /after/ the PHY config packet has been
transmitted, instead of before.  A subsequent fw_core_initiate_bus_reset
will therefore not overlap with the transmission.  This is meant to make
the send PHY config packet + reset bus routine more deterministic.

Fixes bus reset loop and eventual panic with
  - VIA VT6307 + IOGEAR hub + Unibrain Fire-i camera
    http://bugzilla.kernel.org/show_bug.cgi?id=10128
  - JMicron card

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Jarod Wilson <jwilson@redhat.com>