fiemap: Factor out common code used for printing holes

fiemap: Factor out common code used for printing holes

The code responsible for printing holes is scattered across 3 places:
plain print function, verbose print function and in the block handling EOF hole.
Introduce a new function factoring out the common code and replace the 3 sites
where the code is used with it. This reduces duplication and makes it apparent
when we are printing holes. No functional changes.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>