brcmsmac: add support for probe response template

The ucode is able to answer probe response by itself. This writes such
a template into the specific memory. Currently the probe requests are
also send to mac80211 so there are more answers send to a requesting
client. We have to make the ucode stop sending probe requests to the
driver.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>