Add tsi108/9 on chip Ethernet controller driver support.

The driver code collects the feedback of previous posting form the mailing
list and gives the update.

MPC7448HPC2 platform in arch/powerpc uses tsi108 bridge.

The following is a brief description of the Ethernet controller:

The Tsi108/9 Ethernet Controller connects Switch Fabric to two independent
Gigabit Ethernet ports,E0 and E1.  It uses a single Management interface to
manage the two physical connection devices (PHYs).  Each Ethernet port has
its own statistics monitor that tracks and reports key interface
statistics.  Each port supports a 256-entry hash table for address
filtering.  In addition, each port is bridged to the Switch Fabric through
a 2-Kbyte transmit FIFO and a 4-Kbyte Receive FIFO.

Each Ethernet port also has a pair of internal Ethernet DMA channels to
support the transmit and receive data flows.  The Ethernet DMA channels use
descriptors set up in memory, the memory map of the device, and access via
the Switch Fabric.  The Ethernet Controller’s DMA arbiter handles
arbitration for the Switch Fabric.  The Controller also has a register bus
interface for register accesses and status monitor control.

The PMD (Physical Media Device) interface operates in MII, GMII, or TBI
modes.  The MII mode is used for connecting with 10 or 100 Mbit/s PMDs.
The GMII and TBI modes are used to connect with Gigabit PMDs.  Internal
data flows to and from the Ethernet Controller through the Switch Fabric.
Each

Ethernet port uses its transmit and receive DMA channels to manage data
flows through buffer descriptors that are predefined by the system (the
descriptors can exist anywhere in the system memory map).  These
descriptors are data structures that point to buffers filled with data
ready to transmit over Ethernet, or they point to empty buffers ready to
receive data from Ethernet.
Signed-off-by: Alexandre Bounine <Alexandre.Bounine@tundra.com>
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>