iommu/msm: Move the contents from msm_iommu_dev.c to msm_iommu.c

There are only two functions left in msm_iommu_dev.c. Move it to
msm_iommu.c and delete the file.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Tested-by: Archit Taneja <architt@codeaurora.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>