ppc4xx: Consolidate some of the 405 and 440 macros/structs into 4xx

This patch moves some common 4xx macros and the PPC405_SYS_INFO/
PPC440_SYS_INFO structure into the common ppc4xx.h header.

Lot's of other macros are good candidates to be consolidated this way
in the future.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/lwmon5/sdram.c b/board/lwmon5/sdram.c
index d4547e2..399da8a 100644
--- a/board/lwmon5/sdram.c
+++ b/board/lwmon5/sdram.c
@@ -71,7 +71,7 @@
 
 void board_add_ram_info(int use_default)
 {
-	PPC440_SYS_INFO board_cfg;
+	PPC4xx_SYS_INFO board_cfg;
 	u32 val;
 
 	if (is_ecc_enabled())