mac80211: add ieee80211_set_sar_specs

This change registers ieee80211_set_sar_specs to
mac80211_config_ops, so cfg80211 can call it.

Signed-off-by: Carl Huang <cjhuang@codeaurora.org>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Abhishek Kumar <kuabhs@chromium.org>
Link: https://lore.kernel.org/r/20201203103728.3034-3-cjhuang@codeaurora.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>