drm/msm: make iommu port names const'ier

Signed-off-by: Rob Clark <robdclark@gmail.com>
diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
index 7ac2f19..a7a0b6d 100644
--- a/drivers/gpu/drm/msm/msm_iommu.c
+++ b/drivers/gpu/drm/msm/msm_iommu.c
@@ -31,13 +31,15 @@
 	return 0;
 }
 
-static int msm_iommu_attach(struct msm_mmu *mmu, const char **names, int cnt)
+static int msm_iommu_attach(struct msm_mmu *mmu, const char * const *names,
+			    int cnt)
 {
 	struct msm_iommu *iommu = to_msm_iommu(mmu);
 	return iommu_attach_device(iommu->domain, mmu->dev);
 }
 
-static void msm_iommu_detach(struct msm_mmu *mmu, const char **names, int cnt)
+static void msm_iommu_detach(struct msm_mmu *mmu, const char * const *names,
+			     int cnt)
 {
 	struct msm_iommu *iommu = to_msm_iommu(mmu);
 	iommu_detach_device(iommu->domain, mmu->dev);