[SCSI] qla2xxx: Add iIDMA support.

iIDMA (Intelligent Interleaved Direct Memory Access) allows for
the HBA hardware to send FC frames at the rate at which they can
be received by a target device.  By taking advantage of the
higher link rate, the HBA can maximize bandwidth utilization in a
heterogeneous multi-speed SAN.

Within a fabric topology, port speed detection is done via a Name
Server command (GFPN_ID) followed by a Fabric Management command
(GPSC).  In an FCAL/N2N topology, port speed is based on the HBA
link-rate.

Signed-off-by: Andrew Vasquez <andrew.vasquez@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>