AVR32: Enable MMC support

Set up the portmux for the MMC interface and enable the MMC driver
along with support for DOS partitions, ext2 and FAT filesystems.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
diff --git a/board/atmel/atstk1000/atstk1000.c b/board/atmel/atstk1000/atstk1000.c
index 407752c..6618963 100644
--- a/board/atmel/atstk1000/atstk1000.c
+++ b/board/atmel/atstk1000/atstk1000.c
@@ -53,6 +53,9 @@
 	gpio_enable_macb0();
 	gpio_enable_macb1();
 #endif
+#if defined(CONFIG_MMC)
+	gpio_enable_mmci();
+#endif
 
 	return 0;
 }