ppc4xx: Move ppc4xx headers to powerpc include directory

This patch moves some ppc4xx related headers from the common include
directory (include/) to the powerpc specific one
(arch/powerpc/include/asm/). This way to common include directory is not
so cluttered with files.

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/arch/powerpc/cpu/ppc4xx/kgdb.S b/arch/powerpc/cpu/ppc4xx/kgdb.S
index 4227a4c..417ba62 100644
--- a/arch/powerpc/cpu/ppc4xx/kgdb.S
+++ b/arch/powerpc/cpu/ppc4xx/kgdb.S
@@ -22,7 +22,7 @@
 
 #include <config.h>
 #include <command.h>
-#include <ppc4xx.h>
+#include <asm/ppc4xx.h>
 #include <version.h>
 
 #define CONFIG_405GP 1		/* needed for Linux kernel header files */