xfs: check XFS_EOFBLOCKS_RELEASED earlier in xfs_release_eofblocks

If the XFS_EOFBLOCKS_RELEASED flag is set, we are not going to free the
eofblocks, so don't bother locking the inode or performing the checks in
xfs_can_free_eofblocks.  Also switch to a test_and_set operation once
the iolock has been acquire so that only the caller that sets it actually
frees the post-EOF blocks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>