solos: Clean up firmware loading code

We no longer try to load firmware while the ATM is up and running.
However, this means that we _do_ make init_module() wait for it, and it
takes a long time for now (since we're using ultra-conservative code in
the FPGA for that too).

The inner loop which uses swahb32p() was by Simon Farnsworth.

Simon has patches which migrate us to request_firmware_nowait(), for
which we'll actually need to take down the ATM devices, do the upgrade,
then reregister them.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>