nilfs2: remove resize from unsupported features list

Resize feature was supported by the commit 4e33f9eab0 but it was not
reflected to the list of unsupported features in nilfs2.txt file.
This updates the list to fix discrepancy.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Documentation/filesystems/nilfs2.txt

@@ -40,7 +40,6 @@ Features which NILFS2 does not support yet:
 	- POSIX ACLs
 	- quotas
 	- fsck
-	- resize
 	- defragmentation
 
 Mount options