With apps_smmu initializing the SMMU we must specify iommus property for
the sdhc controller.

Fixes: 4429e575 ("arm64: dts: sdm845: Add node for arm,mmu-500")
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>