[SCSI] qla2xxx: add support for multi-queue adapter

Following changes have been made.
1. qla_hw_data structure holds an array for request queue pointers,
and an array for response queue pointers.
2. The base request and response queues are created by default.
3. Additional request and response queues are created at the time of vport
creation. If queue resources are exhausted during vport creation, newly
created vports use the default queue.
4. Requests are sent to the request queue that the vport was assigned
in the beginning.
5. Responses are completed on the response queue with which the request queue
is associated with.

[fixup memcpy argument reversal spotted by davej@redhat.com]
Signed-off-by: Anirban Chakraborty <anirban.chakraborty@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>