[bofm] Report {slot,port} to {bus:dev.fn,mport} mapping on newer BOFM builds

Newer BOFM builds provide support for mapping multiple physical ports
to a single PCI bus:dev.fn via PCI VPD descriptions.  These builds
will also leave the {slot,port} field intact, and will populate the
mport field with a meaningful value.

Older BOFM builds will zero out the {slot,port} field.  A zero value
in this field may indicate either a genuine zero value (i.e. slot 0
first port) or an older build.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/interface/bofm/bofm.c

 			      en.slot, ( en.port + 1 ) );
 			continue;
 		}
+		DBG ( "BOFM: slot %d port %d%s is " PCI_FMT " mport %d\n",
+		      en.slot, ( en.port + 1 ),
+		      ( ( en.slot || en.port ) ? "" : "(?)" ),
+		      PCI_BUS ( en.busdevfn ), PCI_SLOT ( en.busdevfn ),
+		      PCI_FUNC ( en.busdevfn ), en.mport );
 		bofm = bofm_find_busdevfn ( en.busdevfn );
 		if ( ! bofm ) {
-			DBG ( "BOFM: " PCI_FMT " ignored\n",
+			DBG ( "BOFM: " PCI_FMT " mport %d ignored\n",
 			      PCI_BUS ( en.busdevfn ), PCI_SLOT ( en.busdevfn ),
-			      PCI_FUNC ( en.busdevfn ) );
+			      PCI_FUNC ( en.busdevfn ), en.mport );
 			continue;
 		}
 		if ( ( rc = bofm_en ( bofm, &en ) ) == 0 ) {