iommu: msm: perform tlb sync after invalidate

For SMMU, invalidation operation consist of 3 steps.

1) Give invalidation command
2) Give SYNC command
3) Check the status bit and confirm whether TLB operation
  has completed or not.

Fix this sequence in the driver.

Change-Id: I60cefb313b359134367a48528bebe554487d436a
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>