iommu/msm: Add GDSC regulator control

The IOMMU hardware blocks are power-gated by GDSCs which
need to be enabled prior to programming the IOMMU hardware.

Change-Id: I5b4e5a0a60ce672c1180faaf3a8344d72a6ebe5e
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
diff --git a/drivers/iommu/msm_iommu_dev-v2.c b/drivers/iommu/msm_iommu_dev-v2.c
index d6858de..87e1a46 100644
--- a/drivers/iommu/msm_iommu_dev-v2.c
+++ b/drivers/iommu/msm_iommu_dev-v2.c
@@ -75,6 +75,10 @@
 	if (!drvdata->base)
 		return -ENOMEM;
 
+	drvdata->gdsc = devm_regulator_get(&pdev->dev, "vdd");
+	if (IS_ERR(drvdata->gdsc))
+		return -EINVAL;
+
 	drvdata->pclk = clk_get(&pdev->dev, "iface_clk");
 	if (IS_ERR(drvdata->pclk))
 		return PTR_ERR(drvdata->pclk);