Use ext4 for ext2 file systems

configname: CONFIG_EXT4_USE_FOR_EXT2

Linux Kernel Configuration
└─>File systems
└─>Use ext4 for ext2 file systems
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Allow the ext4 file system driver code to be used for ext2
file system mounts. This allows users to reduce their
compiled kernel size by using one file system driver for
ext2, ext3, and ext4 file systems.