ext4: remove write-only variables from ext4_ordered_write_end

The variables 'from' and 'to' are not used anywhere.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>