arm : at91sam9x5 : fix a small bug for NAND

fix a bug:
  when not boot from NAND, the NAND flash can not be detected.
  Using this to fix it

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/board/atmel/at91sam9x5ek/at91sam9x5ek.c b/board/atmel/at91sam9x5ek/at91sam9x5ek.c
index 17db0fd..88b3478 100644
--- a/board/atmel/at91sam9x5ek/at91sam9x5ek.c
+++ b/board/atmel/at91sam9x5ek/at91sam9x5ek.c
@@ -60,6 +60,8 @@
 	/* Enable CS3 */
 	csa = readl(&matrix->ebicsa);
 	csa |= AT91_MATRIX_EBI_CS3A_SMC_SMARTMEDIA;
+	/* NAND flash on D16 */
+	csa |= AT91_MATRIX_NFD0_ON_D16;
 	writel(csa, &matrix->ebicsa);
 
 	/* Configure SMC CS3 for NAND/SmartMedia */