OMAP: iovmm: replace __iounmap with iounmap

__iounmap function is wrong for OMAP architecture,
instead use iounmap which will call to the correct function.
Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
Acked-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>

arch/arm/plat-omap/iovmm.c

@@ -821,7 +821,7 @@ void iommu_kunmap(struct iommu *obj, u32 da)
 	struct sg_table *sgt;
 	typedef void (*func_t)(const void *);
 
-	sgt = unmap_vm_area(obj, da, (func_t)__iounmap,
+	sgt = unmap_vm_area(obj, da, (func_t)iounmap,
 			    IOVMF_LINEAR | IOVMF_MMIO);
 	if (!sgt)
 		dev_dbg(obj->dev, "%s: No sgt\n", __func__);