It's a string of the EXT4 file name. This file use to store the
environment (explicit path to the file)
-if ARCH_ROCKCHIP || ARCH_SUNXI || ARCH_ZYNQ || ARCH_ZYNQMP || ARCH_VERSAL || ARC
+if ARCH_ROCKCHIP || ARCH_SUNXI || ARCH_ZYNQ || ARCH_ZYNQMP || ARCH_VERSAL || ARC || ARCH_STM32MP
config ENV_OFFSET
hex "Environment Offset"