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/cpu/ppc4xx/44x_spd_ddr.c b/cpu/ppc4xx/44x_spd_ddr.c
index 4a4c6f2..65ce46d 100644
--- a/cpu/ppc4xx/44x_spd_ddr.c
+++ b/cpu/ppc4xx/44x_spd_ddr.c
@@ -645,7 +645,7 @@
 	unsigned char refresh_rate_type;
 	unsigned long refresh_interval;
 	unsigned long sdram_rtr;
-	PPC440_SYS_INFO sys_info;
+	PPC4xx_SYS_INFO sys_info;
 
 	/*
 	 * get the board info
@@ -721,7 +721,7 @@
 	unsigned long tcyc_2_0_ns_x_10;
 	unsigned long tcyc_reg;
 	unsigned long bus_period_x_10;
-	PPC440_SYS_INFO sys_info;
+	PPC4xx_SYS_INFO sys_info;
 	unsigned long residue;
 
 	/*
@@ -1065,7 +1065,7 @@
 	unsigned char window_found;
 	unsigned char fail_found;
 	unsigned char pass_found;
-	PPC440_SYS_INFO sys_info;
+	PPC4xx_SYS_INFO sys_info;
 
 	/*
 	 * get the board info