iommu: msm: Add reference counting to IOMMUv1
iommu: msm: Add reference counting to IOMMUv1

Add reference counting to IOMMU attach and detach so that clients
can attach to the same context bank which allows for sharing of
context banks among client.

Change-Id: I38293a0097ff4bba616288f0b1c384db51aeed28
Signed-off-by: Olav Haugan <fbf4ddd114d5f0aa83cb721b7dacab8a264ccf22@codeaurora.org>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas