GFS2: return -E2BIG if hit the maximum limits of ACLs

Return -E2BIG rather than -EINVAL if hit the maximum size limits of
ACLs, as the former errno is consistent with VFS xattr syscalls.

This is pointed out by Dave Chinner in previous discussion thread:
http://www.spinics.net/lists/linux-fsdevel/msg71125.html



Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>