fs/xfs: Fix return code of xfs_break_leased_layouts()

The parens used in the while loop would result in error being assigned
the value 1 rather than the intended errno value.

This is required to return -ETXTBSY from follow on break_layout()
changes.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>