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

Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/board/amcc/taihu/taihu.c b/board/amcc/taihu/taihu.c
index dd2aba5..87c9403 100644
--- a/board/amcc/taihu/taihu.c
+++ b/board/amcc/taihu/taihu.c
@@ -29,7 +29,7 @@
 #include <asm/io.h>
 #include <spi.h>
 #include <netdev.h>
-#include <asm/gpio.h>
+#include <asm/ppc4xx-gpio.h>
 
 extern int lcd_init(void);