dma: Let dma_memory_rw_relaxed() take MemTxAttrs argument

dma: Let dma_memory_rw_relaxed() take MemTxAttrs argument

We will add the MemTxAttrs argument to dma_memory_rw() in
the next commit. Since dma_memory_rw_relaxed() is only used
by dma_memory_rw(), modify it first in a separate commit to
keep the next commit easier to review.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20211223115554.3155328-4-philmd@redhat.com>