kirkwood: make MPP arrays static const

This saves stack and code memory for local copy, and
consumes initialized data memory. For 22 of the 29
kirkwood-based boards, this results in a global saving
of about 30 bytes. For 7 of them, it results in an
increase of 6 to 14 bytes.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
diff --git a/board/Marvell/openrd/openrd.c b/board/Marvell/openrd/openrd.c
index d48f05a..c59a326 100644
--- a/board/Marvell/openrd/openrd.c
+++ b/board/Marvell/openrd/openrd.c
@@ -48,7 +48,7 @@
 			OPENRD_OE_LOW, OPENRD_OE_HIGH);
 
 	/* Multi-Purpose Pins Functionality configuration */
-	u32 kwmpp_config[] = {
+	static const u32 kwmpp_config[] = {
 		MPP0_NF_IO2,
 		MPP1_NF_IO3,
 		MPP2_NF_IO4,