ls102xa: fdt: Disable IFC in SD boot for QSPI

As QSPI/DSPI and IFC are pin multiplexed, IFC is disabled
in SD boot for QSPI. This patch will add fdt support for
this rule.

Signed-off-by: Alison Wang <alison.wang@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>