iommu/omap: Fix build error with !IOMMU_SUPPORT

Without this patch it is possible to select the VIDEO_OMAP3
driver which then selects OMAP_IOVMM. But the omap iommu
driver is not compiled without IOMMU_SUPPORT enabled. Fix
that by forcing OMAP_IOMMU and OMAP_IOVMM are enabled before
VIDEO_OMAP3 can be selected.

Cc: Ohad Ben-Cohen <ohad@wizery.com>
Cc: iommu@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index d901930..ae46776 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -114,8 +114,8 @@
 	select IOMMU_API
 
 config OMAP_IOVMM
-	tristate
-	select OMAP_IOMMU
+	tristate "OMAP IO Virtual Memory Manager Support"
+	depends on OMAP_IOMMU
 
 config OMAP_IOMMU_DEBUG
        tristate "Export OMAP IOMMU/IOVMM internals in DebugFS"