avr32: use board_early_init_r instead of board_init_info

Replace the avr32-specific board_init_info hook by the standard
board_early_init_r hook and make it optional.

board_early_init_r() runs somewhat earlier than board_init_info used to
do, but this isn't a problem for any of the in-tree boards.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
diff --git a/board/miromico/hammerhead/hammerhead.c b/board/miromico/hammerhead/hammerhead.c
index 8670527..7fd0781 100644
--- a/board/miromico/hammerhead/hammerhead.c
+++ b/board/miromico/hammerhead/hammerhead.c
@@ -95,9 +95,10 @@
 	return actual_size;
 }
 
-void board_init_info(void)
+int board_early_init_r(void)
 {
 	gd->bd->bi_phy_id[0] = 0x01;
+	return 0;
 }
 
 int board_postclk_init(void)