ARM: dts: ls1021a: Rename esdhc@1560000 to mmc@1560000

ARM: dts: ls1021a: Rename esdhc@1560000 to mmc@1560000

Rename node name esdhc@1560000 to mmc@1560000 to fix below CHECK_DTBS
warnings:
  arch/arm/boot/dts/nxp/ls/ls1021a-tqmls1021a-mbls1021a-rgb-cdtech-fc21.dtb: esdhc@1560000 (fsl,ls1021a-esdhc): $nodename:0: 'esdhc@1560000' does not match '^mmc(@.*)?$'
	from schema $id: http://devicetree.org/schemas/mmc/fsl,esdhc.yaml#

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>