board/olpc/xo-1: enable JFFS2

The XO-1 laptop has a NAND flash and firmware capable of reading JFFS2
from it. Enable JFFS2 kernel support so that we'll be able to create
images capable of booting from the internal flash.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

board/olpc/xo-1/linux.config

@@ -70,6 +70,7 @@ CONFIG_RESET_CONTROLLER=y
 CONFIG_GENERIC_PHY=y
 CONFIG_PROC_KCORE=y
 CONFIG_HUGETLBFS=y
+CONFIG_JFFS2_FS=y
 CONFIG_JFFS2_FS_WBUF_VERIFY=y
 CONFIG_JFFS2_SUMMARY=y
 CONFIG_JFFS2_FS_XATTR=y