We need the signal from wcnss_ctrl indicating that the firmware is up
and running before we can communicate with the other components of the
chip. So make these other components children of the wcnss_ctrl device,
so they can be probed in order.

The process seems to take between 1/2-5 seconds, so this is done in a
worker, instead of holding up the probe.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>