ARM: dts: imx51-babbage: fix esdhc cd/wp properties

The binding doc and dts use properties "fsl,{cd,wp}-internal" while
esdhc driver uses "fsl,{cd,wp}-controller".  Fix binding doc and dts
to get them match driver code.

Reported-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: <stable@vger.kernel.org>
Acked-by: Chris Ball <cjb@laptop.org>