Add missing rainier (PPC440GRx) target to MAKEALL and MAINTAINERs files

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/MAKEALL b/MAKEALL
index 1219fb3..ea37513 100755
--- a/MAKEALL
+++ b/MAKEALL
@@ -204,6 +204,7 @@
 	PLU405		\
 	PMC405		\
 	PPChameleonEVB	\
+	rainier		\
 	sbc405		\
 	sc3		\
 	sequoia		\