fs/erofs: add lz4 decompression support

Support EROFS lz4 compressed files.

Signed-off-by: Huang Jianan <jnhuang95@gmail.com>
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 7398ab7..58af6a6 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -4,4 +4,6 @@
 obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \
 				super.o \
 				namei.o \
-				data.o
+				data.o \
+				decompress.o \
+				zmap.o