arm64: dts: marvell: espressobin: De-duplicate eMMC definitions

eMMC definitions in files armada-3720-espressobin-emmc.dts and
armada-3720-espressobin-v7-emmc.dts is same. So move it into common
armada-3720-espressobin.dtsi file with status "disabled".

This change simplifies eMMC variants of DTS files for Espressobin.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Andre Heider <a.heider@gmail.com>
Tested-by: Andre Heider <a.heider@gmail.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>