ARM: dts: socfpga: Fix SD card detect

Without this patch, the booting the SOCFPGA platform would hang at the
SDMMC driver loading. The issue, debugged by Doug Anderson, turned out
to be that the GPIO bank used by the SD card-detect was not set to
status="okay".

Also update the cd-gpios to point to portb of the &gpio1 GPIO IP.

Suggested-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
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v4: Use &gpio1 to set status="okay" and update cd-gpio=&portb
v3: Correctly degugged the issue to be a gpio node not having status="okay"