OMAP: iommu: create new api to set valid da range

Some IOMMUs cannot use the whole 0x0 - 0xFFFFFFFF range.
With this new API the valid range can be set.

Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
Acked-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>