kernel: add the ubifs EOF marker support to 3.14 kernel

Without this patch the UBIFS driver is unable to attach to the mtd
storage and mount the root FS.

Fixes a kernel panic with Netgear WNDR4300/3700v4 devices.

Signed-off-by: Gianluca Anzolin <gianluca@sottospazio.it>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@43287 3c298f89-4303-0410-b956-a3cf2f4a3e73