common: add zip command support

Signed-off-by: Lei Wen <leiwen@marvell.com>
diff --git a/common/Makefile b/common/Makefile
index b56df1d..125b2be 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -170,6 +170,7 @@
 COBJS-$(CONFIG_CMD_XIMG) += cmd_ximg.o
 COBJS-$(CONFIG_YAFFS2) += cmd_yaffs2.o
 COBJS-$(CONFIG_CMD_SPL) += cmd_spl.o
+COBJS-$(CONFIG_CMD_ZIP) += cmd_zip.o
 COBJS-$(CONFIG_CMD_ZFS) += cmd_zfs.o
 
 # others