ARM: atmel: at91sam9n12ek: enable spl support

Enable SPL support for at91sam9n12ek boards, now it supports
boot up from NAND flash, serial flash.

Signed-off-by: Bo Shen <voice.shen@atmel.com>
diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile
index ba83616..0d3ee48 100644
--- a/arch/arm/mach-at91/Makefile
+++ b/arch/arm/mach-at91/Makefile
@@ -2,6 +2,7 @@
 ifneq ($(CONFIG_SPL_BUILD),)
 obj-$(CONFIG_AT91SAM9G20) += sdram.o spl_at91.o
 obj-$(CONFIG_AT91SAM9M10G45) += mpddrc.o spl_at91.o
+obj-$(CONFIG_AT91SAM9N12) += mpddrc.o spl_at91.o
 obj-$(CONFIG_AT91SAM9X5) += mpddrc.o spl_at91.o
 obj-$(CONFIG_SAMA5D3) += mpddrc.o spl_atmel.o
 obj-$(CONFIG_SAMA5D4) += mpddrc.o spl_atmel.o