mkfs.f2fs: fix wrong documentation

The -s should be the number of segments per a section.

Change-Id: I2b0b46c3c2c08595d434a112d6974817fd06177a
Reported-by: Marc Lehmann <schmorp@schmorp.de>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
1 file changed