iommu/fsl: Freescale PAMU driver and iommu implementation.

Following is a brief description of the PAMU hardware:
PAMU determines what action to take and whether to authorize the action on
the basis of the memory address, a Logical IO Device Number (LIODN), and
PAACT table (logically) indexed by LIODN and address. Hardware devices which
need to access memory must provide an LIODN in addition to the memory address.

Peripheral Access Authorization and Control Tables (PAACTs) are the primary
data structures used by PAMU. A PAACT is a table of peripheral access
authorization and control entries (PAACE).Each PAACE defines the range of
I/O bus address space that is accessible by the LIOD and the associated access
capabilities.

There are two types of PAACTs: primary PAACT (PPAACT) and secondary PAACT
(SPAACT).A given physical I/O device may be able to act as one or more
independent logical I/O devices (LIODs). Each such logical I/O device is
assigned an identifier called logical I/O device number (LIODN). A LIODN is
allocated a contiguous portion of the I/O bus address space called the DSA window
for performing DSA operations. The DSA window may optionally be divided into
multiple sub-windows, each of which may be used to map to a region in system
storage space. The first sub-window is referred to as the primary sub-window
and the remaining are called secondary sub-windows.

This patch provides the PAMU driver (fsl_pamu.c) and the corresponding IOMMU
API implementation (fsl_pamu_domain.c). The PAMU hardware driver (fsl_pamu.c)
has been derived from the work done by Ashish Kalra and Timur Tabi.

[For iommu group support]
Acked-by: Alex Williamson <alex.williamson@redhat.com>

Signed-off-by: Timur Tabi <timur@tabi.org>
Signed-off-by: Varun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>