xfs: remove the flags argument to xfs_buf_get_uncached

No callers passes flags to xfs_buf_get_uncached, which makes sense
given that the flags apply to behavior not used for uncached buffers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>