ppc4xx: Generic architecture for xilinx ppc405(v3)

As "ppc44x: Unification of virtex5 pp440 boards" did for the xilinx
ppc440 boards, this patch presents a common architecture for all the
xilinx ppc405 boards.

Any custom xilinx ppc405 board can be added very easily with no code
duplicity.

This patch also adds a simple generic board, that can be used on almost
any design with xilinx ppc405 replacing the file ppc405-generic/xparameters.h

This patch is prepared to work with the latest version of EDK (10.1)

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@uam.es>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/cpu/ppc4xx/start.S b/cpu/ppc4xx/start.S
index 31902a0..882ef21 100644
--- a/cpu/ppc4xx/start.S
+++ b/cpu/ppc4xx/start.S
@@ -918,7 +918,8 @@
 	ori	r4, r4, CONFIG_SYS_DCACHE_SACR_VALUE@l
 	mtdccr	r4
 
-#if !(defined(CONFIG_SYS_EBC_PB0AP) && defined(CONFIG_SYS_EBC_PB0CR))
+#if !(defined(CONFIG_SYS_EBC_PB0AP) && defined(CONFIG_SYS_EBC_PB0CR))\
+				&& !defined (CONFIG_XILINX_405)
 	/*----------------------------------------------------------------------- */
 	/* Tune the speed and size for flash CS0  */
 	/*----------------------------------------------------------------------- */