ARM: dts: db600c: Add eMMC and SD card support

This patch adds eMMC and SD card support with card detect and adding
required regulators.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>