backports: backports: reshufle the threaded IRQ backport series

backports: backports: reshufle the threaded IRQ backport series

This reshufles the patches that deal with backported threaded
IRQ support. The purpose of this reshufle is to try get them
into a consistent style. Only the b43 driver takes a major
change in that the the workqueue used for threading work
is now also destroyed upon its b43_wireless_core_stop() call.
This change was tested by pkgadd from #linux-wireless on b43 on
an older kernel. The b43 driver just fails to unload but that
issue was present before this change.

The non-general changes to the b43 driver are also moved
out to a helper patch to help separate the general
collateral evolution changes from driver specific required
changes.

Cc: Peter Senna <peter.senna@gmail.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Gilles Muller <Gilles.Muller@lip6.fr>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>