ext3: pass custom EOF to generic_file_llseek_size()

Use the new custom EOF argument to generic_file_llseek_size so
that SEEK_END will go to the max hash value for htree dirs
in ext3 rather than to i_size_read()

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>