[spi] reformat message and ar5315_spi minor fix

This commit corrects print of nomatch (newline was too early) and fix
unit number for new child in ar5315_spi (was 0, now is -1 to calculate it
according to actual system state)

Submitted by:	Hiroki Mori <yamori813@yahoo.co.jp>
Reviewed by:	ray, loos, mizhka
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D8749

sys/dev/spibus/spibus.c

@@ -117,8 +117,8 @@ spibus_probe_nomatch(device_t bus, device_t child)
 	struct spibus_ivar *devi = SPIBUS_IVAR(child);
 
 	device_printf(bus, "<unknown card>");
-	printf(" at cs %d\n", devi->cs);
-	printf(" mode %d", devi->mode);
+	printf(" at cs %d", devi->cs);
+	printf(" mode %d\n", devi->mode);
 	return;
 }
 

sys/mips/atheros/ar531x/ar5315_spi.c

@@ -122,7 +122,7 @@ ar5315_spi_attach(device_t dev)
 		return (ENXIO);
 	}
 
-	device_add_child(dev, "spibus", 0);
+	device_add_child(dev, "spibus", -1);
 	ar5315_spi_attach_sysctl(dev);
 
 	return (bus_generic_attach(dev));