brcmfmac: respect hidden_ssid for AP interfaces

This was succesfully tested with 4366B1. A small workaround is needed
for the main interface otherwise it would stuck at the hidden state.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>