iommu: qcom: fix compiler warnings.

This patch fixes below compiler error.
drivers/iommu/qcom_iommu_v0.c:941:2: error: unknown field ‘domain_has_cap’ specified in initialiser
drivers/iommu/qcom_iommu_v0.c:941:2: warning: initialisation from incompatible pointer type [enabled by default]
drivers/iommu/qcom_iommu_v0.c:941:2: warning: (near initialisation for ‘qcom_iommu_ops.add_device’) [enabled by default]

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>