arm: dts: a37x0: enable sd card support on espressobin

Enabled SDIO slot 0 (south bridge) for SD card on
Espressobin board.

Change-Id: I51a2debf9fba276b9c4a2bc6da91328d47f443e3
Signed-off-by: Wilson Ding <dingwei@marvell.com>
Signed-off-by: Konstantin Porotchkin <kostap@marvell.com>
Reviewed-on: http://vgitil04.il.marvell.com:8080/60945


Tested-by: iSoC Platform CI <ykjenk@marvell.com>
Reviewed-by: Igal Liberman <igall@marvell.com>
[pali: Define cd-gpios and enable CONFIG_DM_REGULATOR_GPIO]
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Konstantin Porotchkin <kostap@marvell.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Andre Heider <a.heider@gmail.com>