firewire: sbp2: identify to driver core as "firewire_sbp2", not "sbp2"

Commit eba9ebaa

 "firewire: sbp2: use dev_printk API" changed
messages from e.g.
    firewire_sbp2: fw3.0: logged in to LUN 0000 (0 retries)
to
    sbp2 fw3.0: logged in to LUN 0000 (0 retries)
because the driver calls itself as "sbp2" when registering with driver
core and with SCSI core.  This is of course confusing, so switch to the
name "firewire_sbp2" for driver core in order to match what lsmod and
/sys/module/ show.  So we are back to
    firewire_sbp2 fw3.0: logged in to LUN 0000 (0 retries)
in the kernel log.

This also changes
    /sys/bus/firewire/drivers/sbp2
    /sys/bus/firewire/devices/fw3.0/driver -> [...]/sbp2
    /sys/module/firewire_sbp2/drivers/firewire:sbp2
to
    /sys/bus/firewire/drivers/firewire_sbp2
    /sys/bus/firewire/devices/fw3.0/driver -> [...]/firewire_sbp2
    /sys/module/firewire_sbp2/drivers/firewire:firewire_sbp2

but "cat /sys/class/scsi_host/host27/proc_name" stays "sbp2" just in
case that proc_name is used by any userland.

The transport detection in lsscsi is not affected.  (Tested with lsscsi
version 0.25.)  Udev's /dev/disk/by-id and by-path symlinks are not
affected either.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>