linux

This allows using all available memory.

The IOMMU is part of the decoder core but can be driven by the rockchip
iommu driver as a separate device.

The only issue with this is that the IOMMU hardware is reset when the
decoder is reset because of an error.
In this case, the IOMMU hardware looses all mappings but the mapped buffer
still retain their mapped address, cached in the IOMMU and decoder drivers.

To avoid that, when a decoding error occurs, the iommu_flush_iotlb_all
callback is used on the IOMMU to reconfigure the HW before continuing.

Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>