imx6: aristainetos: add aristainetos 2b csl

arch/arm/dts/Makefile

arch/arm/dts/imx6dl-aristainetos2b_csl_4-u-boot.dtsi

arch/arm/dts/imx6dl-aristainetos2b_csl_4.dts

arch/arm/dts/imx6dl-aristainetos2b_csl_7-u-boot.dtsi

arch/arm/dts/imx6dl-aristainetos2b_csl_7.dts

arch/arm/dts/imx6qdl-aristainetos2b_csl-u-boot.dtsi

arch/arm/dts/imx6qdl-aristainetos2b_csl.dtsi

arch/arm/mach-imx/mx6/Kconfig

board/aristainetos/Kconfig

board/aristainetos/MAINTAINERS

board/aristainetos/aristainetos.c

board/aristainetos/common/Kconfig

configs/aristainetos2bcsl_defconfig

include/configs/aristainetos2.h