hw/arm/fsl-imx25: Wire up eSDHC controllers

hw/arm/fsl-imx25: Wire up eSDHC controllers

Wire up eSDHC controllers in fsl-imx25. For imx25-pdk, connect drives
provided on the command line to available eSDHC controllers.

This patch enables booting the imx25-pdk emulation from SD card.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Message-id: 20200310215146.19688-2-linux@roeck-us.net
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: made commit subject consistent with other patch]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>