brcmfmac: properly check for bus register errors

The brcmfmac driver ignores any errors on initialization with the
different busses by deferring the initialization to a workqueue and
ignoring all possible errors that might happen.  Fix up all of this by
only allowing the module to load if all bus registering worked properly.

Cc: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210503115736.2104747-70-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>