fs-lib: install crc32c for ext4

EXT4 filesystems created with metadata_csum (enabled by default in mke2fs 1.44+) or ea_inode need crc32c.

https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/commit/?id=d0b9e0a6aa7d6805338a43b4e372623352d8df09
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/tree/fs/ext4/super.c?h=v4.15.15#n3491

modules.d/99fs-lib/module-setup.sh

@@ -38,7 +38,7 @@ echo_fs_helper() {
 include_fs_helper_modules() {
     local dev=$1 fs=$2
     case "$fs" in
-        xfs|btrfs)
+        xfs|btrfs|ext4)
             instmods crc32c
             ;;
         f2fs)