mvebu: cortex-a72: enable U-Boot NVMEM driver
In order to not have to ship envtools configuration per board, we can
instead rely on the kernel U-Boot environment NVMEM driver through which
envtools can read/write the environement.
Since size difference is negligeble and this subtarget has rather large
storage regardless, enable it by default.
Link: https://github.com/openwrt/openwrt/pull/15765
Signed-off-by: Robert Marko <[email protected]>
Robert Marko