CVE-2023-53143 ext4: fix another off-by-one fsmap error on 1k block filesystems

In the Linux kernel, the following vulnerability has been resolved: ext4: fix another off-by-one fsmap error on 1k block filesystems Apparently syzbot figured out that issuing this FSMAP call: struct fsmaphead cmd = .fmhcount = ...; .fmhkeys = .fmrdevice = / ext4 dev /, .fmrphysical = 0, ,...