nl80211: NAN: Register multicast action frames if possible

nl80211: NAN: Register multicast action frames if possible

The USD passive subscriber and solicited transmission only publisher
require receiving multicast NAN action frames in order to work.
Currently, we are not requesting to receive multicast when
registering NAN action frames. As a result, USD passive subscribe or
solicited only publish may not work.

The NL80211_ATTR_RECEIVE_MULTICAST attribute corresponds to wiphy
ext feature NL80211_EXT_FEATURE_MULTICAST_REGISTRATIONS, which
requires driver support and only a few drivers in the kernel tree
support it. Namely ath9k, ath9k_htc, ath10k and hwsim. We should
fall back to register non multicast action frames if the driver
has no support.

It was confirmed that ath9k_htc starts to work after the changes.

Note that even without requesting to receive multicast Action
frames, some drivers would still upload them. For example, rtl8192cu
and hwsim. This is why test cases like test_nan_usd_match would not
fail.

Tested-on: TP-LINK TL-WN821N v3(AR7010+AR9287, ath9k_htc)
Signed-off-by: Chien Wong <m@xv97.com>