IOMMU build iommu as part of the kernel by default

This patch enables the IOMMU by default in kernel
configuration.
Signed-off-by: Ramesh Gupta G <grgupta@ti.com>

arch/arm/plat-omap/Kconfig

@@ -119,7 +119,8 @@ config OMAP_MBOX_FWK
 
 config OMAP_IOMMU
 	tristate "iommu"
-        depends on ARCH_OMAP
+    depends on ARCH_OMAP
+	default y
 choice
         prompt "System timer"
 	default OMAP_MPU_TIMER