pegasus: minor resource shrinkage

Make pegasus driver not allocate a workqueue until the driver
is bound to some device, which will need that workqueue if
the device is brought up.  This conserves resources when the
driver is linked but there's no pegasus device connected.

Also shrink the runtime footprint a smidgeon by moving some
init-only code into its proper section, and move an obnoxious
(frequent and meaningless) message to be debug-only.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>