[SCSI] libfc: change debug messages to give host number.

libfc debug messages currently show 'lport: <fc-id>:'
wher <fc-id> is the hex assigned port-id.  When the lport
is logged off, that will be zero, so its hard to distinguish
which instance is involved.  The FC-ID can change
if the port is re-patched or changes VSANs.

Two lports may even have the same FC-ID if connected to isolated SANs.

Change the debug messages to print the SCSI host number "hostN:",
which will not change for the life of the lport.
Still show the FC_ID on lport messages.

Also, add a macro to FC_RPORT_ID_DBG for rport debugging where there's
no rdata structure involved.  It takes the lport and port_id as parameters.
Use this in fc_rport_recv_plogi_req() and fc_rport_recv_logo_req().

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>