iwlwifi: fix FIFO vs. queue confusion

When I added that code setting the swq_id, I evidently
did not understand the distinction between FIFO and TX
queue yet and added code to compare a queue ID and a
FIFO number, which is bogus.

However, the code there need not be this specific, it
can just set all queues to the identity mapping which
will be overwritten by the aggregation queue code. As
a bit of defensive coding, don't assign an swq_id to
the command queue so that if we ever use it for frames
we notice quickly.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>