Documentation: dmaengine: Correctly describe dmatest with channel unset

stable inclusion
from stable-v5.10.94
commit d1e85fcd73b5c94dc5032a63ecb3df4cbceda82d
bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d1e85fcd73b5c94dc5032a63ecb3df4cbceda82d



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commit c61d7b2e upstream.

Currently the documentation states that channels must be configured before
running the dmatest. This has not been true since commit 6b41030f
("dmaengine: dmatest: Restore default for channel"). Fix accordingly.

Fixes: 6b41030f ("dmaengine: dmatest: Restore default for channel")
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20211118100952.27268-3-daniel.thompson@linaro.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>