iommu/arm-smmu: Move arm_iommu_put_cookie() to the SMMU driver

The SMMU driver is the only user of the arm_iommu_put_cookie(),
thus move it to the SMMU driver.

Change-Id: I92d37bcbe3cdfa92349811a1fae90645ad026230
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>