libxfs: make xfs_alloc_fix_freelist non-static

Since xfs_repair wants to use xfs_alloc_fix_freelist, remove the
static designation.  xfsprogs already has this; this simply brings
the kernel up to date.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>