add a new AT91 GPIO driver

* add a real AT91 GPIO driver instead of header inline code
* resolve the mixing of port and pins
* change board config files to use new driver
* add macros to gpio to realize backward compatibility

Signed-off-by: Jens Scharsig <js_at_ng@scharsoft.de>
diff --git a/include/configs/afeb9260.h b/include/configs/afeb9260.h
index 3b69de8..9f8c567 100644
--- a/include/configs/afeb9260.h
+++ b/include/configs/afeb9260.h
@@ -47,6 +47,7 @@
 /*
  * Hardware drivers
  */
+#define CONFIG_AT91_GPIO	1
 #define CONFIG_ATMEL_USART	1
 #undef CONFIG_USART0
 #undef CONFIG_USART1