repair: handle sparse format inobt record freecount correctly

repair: handle sparse format inobt record freecount correctly

The sparse inode chunk feature introduces a new inobt record format that
converts ir_freecount from 4 bytes to 1 byte. ir_freecount references
throughout repair currently assume the 'full' format and endian-convert
from the 32-bit value.

Update the xfs_repair inobt scan and tree rebuild codepaths to use the
correct record format for ir_freecount when sparse inodes is enabled.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>