ppc4xx: Move gpio.h to ppc4xx-gpio.h since its ppc4xx specific

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/lwmon5/lwmon5.c b/board/lwmon5/lwmon5.c
index aec0263..0c6f4e5 100644
--- a/board/lwmon5/lwmon5.c
+++ b/board/lwmon5/lwmon5.c
@@ -22,7 +22,7 @@
 #include <command.h>
 #include <asm/ppc440.h>
 #include <asm/processor.h>
-#include <asm/gpio.h>
+#include <asm/ppc4xx-gpio.h>
 #include <asm/io.h>
 
 DECLARE_GLOBAL_DATA_PTR;