[POWERPC] Fix modalias content in sysfs for macio devices

Currently the buf pointer is advanced too far during each iteration.
Also terminate the string with a newline.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/macintosh/macio_sysfs.c b/drivers/macintosh/macio_sysfs.c
index 8566bdf..0a5647f 100644
--- a/drivers/macintosh/macio_sysfs.c
+++ b/drivers/macintosh/macio_sysfs.c
@@ -53,12 +53,14 @@
 	buf += length;
 	while (cplen > 0) {
 		int l;
-		length += sprintf (buf, "C%s", compat);
-		buf += length;
+		l = sprintf (buf, "C%s", compat);
+		length += l;
+		buf += l;
 		l = strlen (compat) + 1;
 		compat += l;
 		cplen -= l;
 	}
+	length += sprintf(buf, "\n");
 
 	return length;
 }