Description: ubi: Check for too small LEB size in VTBL code
References:
 https://www.spinics.net/lists/kernel/msg5074816.html
 https://groups.google.com/g/syzkaller/c/Xl97YcQA4hg
Notes:
 carnil> Commit fixes 801c135ce73d ("UBI: Unsorted Block Images")
Bugs:
upstream: needed
6.1-upstream-stable: needed
5.10-upstream-stable: needed
4.19-upstream-stable: needed
sid: needed
6.1-bookworm-security: needed
5.10-bullseye-security: needed
4.19-buster-security: needed