cfg80211: add bss_type and privacy arguments in cfg80211_get_bss()

cfg80211: add bss_type and privacy arguments in cfg80211_get_bss()

802.11ad adds new a network type (PBSS) and changes the capability
field interpretation for the DMG (60G) band.
The same 2 bits that were interpreted as "ESS" and "IBSS" before are
re-used as a 2-bit field with 3 valid values (and 1 reserved). Valid
values are: "IBSS", "PBSS" (new) and "AP".

In order to get the BSS struct for the new PBSS networks, change the
cfg80211_get_bss() function to take a new enum ieee80211_bss_type
argument with the valid network types, as "capa_mask" and "capa_val"
no longer work correctly (the search must be band-aware now.)

The remaining bits in "capa_mask" and "capa_val" are used only for
privacy matching so replace those two with a privacy enum as well.

Signed-off-by: Dedy Lansky <dlansky@codeaurora.org>
[rewrite commit log, tiny fixes]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>