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/post/cpu/ppc4xx/fpu.c b/post/cpu/ppc4xx/fpu.c
index e9b96dd..9f49690 100644
--- a/post/cpu/ppc4xx/fpu.c
+++ b/post/cpu/ppc4xx/fpu.c
@@ -29,7 +29,7 @@
     defined(CONFIG_440EPX)
 
 #include <asm/processor.h>
-#include <ppc4xx.h>
+#include <asm/ppc4xx.h>
 
 
 int fpu_status(void)