Supply a separate sg list for each of the request in non-blocking
IO test cases where two requests will be issued at same time.

Otherwise, sg memory may get unmapped when a request is done while
same memory is being accessed by controller from the other request,
and it leads to iommu errors with below call stack:

	__arm_lpae_unmap+0x2e0/0x478
	arm_lpae_unmap+0x54/0x70
	arm_smmu_unmap+0x64/0xa4
	__iommu_unmap+0xb8/0x1f0
	iommu_unmap_fast+0x38/0x48
	__iommu_dma_unmap+0x88/0x108
	iommu_dma_unmap_sg+0x90/0xa4
	sdhci_post_req+0x5c/0x78
	mmc_test_start_areq+0x10c/0x120 [mmc_test]
	mmc_test_area_io_seq+0x150/0x264 [mmc_test]
	mmc_test_rw_multiple+0x174/0x1c0 [mmc_test]
	mmc_test_rw_multiple_sg_len+0x44/0x6c [mmc_test]
	mmc_test_profile_sglen_wr_nonblock_perf+0x6c/0x94 [mmc_test]
	mtf_test_write+0x238/0x3cc [mmc_test]
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/1582714668-17247-1-git-send-email-vbadigan@codeaurora.orgSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>