fs/erofs: add filesystem commands

Add 'ls' and 'load' commands.

Signed-off-by: Huang Jianan <jnhuang95@gmail.com>
diff --git a/cmd/Makefile b/cmd/Makefile
index 0d2b2ee..ede634d 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -61,6 +61,7 @@
 obj-$(CONFIG_EFI) += efi.o
 obj-$(CONFIG_CMD_EFIDEBUG) += efidebug.o
 obj-$(CONFIG_CMD_ELF) += elf.o
+obj-$(CONFIG_CMD_EROFS) += erofs.o
 obj-$(CONFIG_HUSH_PARSER) += exit.o
 obj-$(CONFIG_CMD_EXT4) += ext4.o
 obj-$(CONFIG_CMD_EXT2) += ext2.o