iommu/tegra: fix device leak on probe_device()

iommu/tegra: fix device leak on probe_device()

Make sure to drop the reference taken to the iommu platform device when
looking up its driver data during probe_device().

Note that commit 9826e393e4a8 ("iommu/tegra-smmu: Fix missing
put_device() call in tegra_smmu_find") fixed the leak in an error path,
but the reference is still leaking on success.

Fixes: 891846516317 ("memory: Add NVIDIA Tegra memory controller support")
Cc: stable@vger.kernel.org	# 3.19: 9826e393e4a8
Cc: Miaoqian Lin <linmq006@gmail.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>