driver core: faux: stop using static struct device

driver core: faux: stop using static struct device

faux_bus_root should not have been a static struct device, but rather a
dynamically created structure so that lockdep and other testing tools do
not trip over it (as well as being the right thing overall to do.)  Fix
this up by making it properly dynamic.

Reported-by: Gui-Dong Han <hanguidong02@gmail.com>
Closes: https://lore.kernel.org/lkml/CALbr=LYKJsj6cbrDLA07qioKhWJcRj+gW8=bq5=4ZvpEe2c4Yg@mail.gmail.com/
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://patch.msgid.link/2026012145-lapping-countless-ef81@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>