iommu/arm-smmu: Remove support for qcom,smmu-v2

Remove the support for qsmmuv2 in the arm-smmu
driver since no chipsets using msm-kona or higher
kernels are expected to use qsmmuv2.

Change-Id: I7f83bba8120ef0b5718b493b2d57aa462b011909
Signed-off-by: Swathi Sridhar <swatsrid@codeaurora.org>