Pads SD2_CLK/CMD/DAT0-3 are connected to an SDIO WiFi device on
Nitrogen and unconnected on BD-SL-i.MX6 (sabre lite).
Configure them as SDIO pins to prevent them from being in a state
that confuses the WiFi part.
Signed-off-by: Eric Nelson <eric.nelson@boundarydevices.com>