net_dma: call dmaengine_get only if NET_DMA enabled

Based upon a patch from Atsushi Nemoto <anemo@mba.ocn.ne.jp>

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The commit 649274d993212e7c23c0cb734572c2311c200872 ("net_dma:
acquire/release dma channels on ifup/ifdown") added unconditional call
of dmaengine_get() to net_dma.  The API should be called only if
NET_DMA was enabled.
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Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Dan Williams <dan.j.williams@intel.com>
2 files changed