Patch merged into coreboot/master: asus/f2a85-m_le: Activate IOMMU support

the following patch was just integrated into master:
commit 31db6f5e179d6e0162c010583a31e1f3addf03b7
Author: Tobias Diedrich 
Date:   Sun Jan 29 18:03:09 2017 +0100

asus/f2a85-m_le: Activate IOMMU support

Activate the IOMMU for the ASUS F2A85-M LE board.

Enable the IOMMU in `devicetree.cb` and build AGESA IOMMU code by
    enabling the option in `buildOpts.c`.

ACPI and MPTABLES interrupt routers are already present since they are
    syminks to the F2A85-M version.

```
    $ uname -a
    Linux nukunuku 4.8.5 #35 SMP Sun Oct 30 19:34:55 CET 2016 x86_64 GNU/Linux
    $ lspci -s 0.2
    00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Family 15h (Models 10h-1fh) I/O Memory Management Unit
    $ dmesg | grep -i IOMMU
    ACPI: IVRS 0x00000000BFFAFF70 000070 (v02 AMD    AMDIOMMU 00000001 AMD  00000000)
    AMD-Vi: Applying erratum 746 workaround for IOMMU at 0000:00:00.2
    iommu: Adding device 0000:00:01.0 to group 0
    [...]
    iommu: Adding device 0000:00:18.5 to group 9
    iommu: Adding device 0000:03:00.0 to group 8
    AMD-Vi: Found IOMMU at 0000:00:00.2 cap 0x40
    AMD IOMMUv2 driver by Joerg Roedel 
    ```

Change-Id: I6049fcfad53d16a99495d7a8fbc584c71e371d73
    Signed-off-by: Tobias Diedrich 
    Reviewed-on: https://review.coreboot.org/18259
    Tested-by: build bot (Jenkins)
    Reviewed-by: Paul Menzel 
    Reviewed-by: Martin Roth

See https://review.coreboot.org/18259 for details.

-gerrit