arm, at91, axm: add SPL support for axm

add SPL support also for the axm board.

Signed-off-by: Heiko Schocher <hs@denx.de>
diff --git a/configs/axm_defconfig b/configs/axm_defconfig
index c0e8da2..076ad0f 100644
--- a/configs/axm_defconfig
+++ b/configs/axm_defconfig
@@ -1,3 +1,4 @@
+CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="AT91SAM9G20,MACH_TYPE=2068,BOARD_AXM"
-CONFIG_ARM=y
-CONFIG_TARGET_TAURUS=y
++S:CONFIG_ARM=y
++S:CONFIG_TARGET_TAURUS=y