arm64: do not set SWIOTLB_NO_FORCE when swiotlb is required

Although SWIOTLB_NO_FORCE is meant to allow later calls to swiotlb_init,
today dma_direct_map_page returns error if SWIOTLB_NO_FORCE.

For now, without a larger overhaul of SWIOTLB_NO_FORCE, the best we can
do is to avoid setting SWIOTLB_NO_FORCE in mem_init when we know that it
is going to be required later (e.g. Xen requires it).

CC: boris.ostrovsky@oracle.com
CC: jgross@suse.com
CC: catalin.marinas@arm.com
CC: will@kernel.org
CC: linux-arm-kernel@lists.infradead.org
Fixes: 2726bf3f

 ("swiotlb: Make SWIOTLB_NO_FORCE perform no allocation")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210512201823.1963-2-sstabellini@kernel.org


Signed-off-by: Juergen Gross <jgross@suse.com>