xfs_db: consolidate set_iocur_type behavior

xfs_db: consolidate set_iocur_type behavior

Right now there are 3 cases to type_f: inode type, type with fields,
and a default.  The first two were added to address issues with handling
V5 metadata.

The first two already use some version of set_cur, which handles all
of the validation etc. There's no reason to leave the open-coded bits
at the end, just send every non-inode type through set_cur and be done
with it.

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