remoteproc: qcom_wcnss: Fix circular module dependency

The tie between the main WCNSS driver and the IRIS driver causes a
circular dependency between the two modules. Neither part makes sense to
have on their own so lets merge them into one module.

For the sake of picking up the clock and regulator resources described
in the iris of_node we need an associated struct device. But, to keep
the size of the patch down we continue to represent the IRIS part as its
own platform_driver, within the same module, rather than setting up a
dummy device.

Fixes: aed361ad ("remoteproc: qcom: Introduce WCNSS peripheral image loader")
Reported-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>