OMAP: iommu: make iva2 iommu selectable

It seems dsp-link will do this, and tidspbridge too at some point, but
right now it's not possible to select CONFIG_MPU_BRIDGE_IOMMU.

Cc: Fernando Guzman Lugo <fernando.lugo@ti.com>
Cc: Yogesh Marathe <yogesh_marathe@ti.com>
Signed-off-by: Felipe Contreras <felipe.contreras@nokia.com>

arch/arm/mach-omap2/omap-iommu.c

@@ -37,7 +37,7 @@ static struct iommu_device omap3_devices[] = {
 			.da_end = 0xFFFFF000,
 		},
 	},
-#if defined(CONFIG_MPU_BRIDGE_IOMMU)
+#if defined(CONFIG_OMAP_IOMMU_IVA2)
 	{
 		.base = 0x5d000000,
 		.irq = 28,

arch/arm/plat-omap/Kconfig

@@ -109,6 +109,9 @@ config OMAP_IOMMU_DEBUG
 
          Say N unless you know you need this.
 
+config OMAP_IOMMU_IVA2
+	bool
+
 choice
 	prompt "System timer"
 	default OMAP_32K_TIMER if !ARCH_OMAP15XX