cfg80211: move cookie_counter out of wiphy

There's no reason for drivers to be able to access the
cfg80211 internal cookie counter; move it out of the
wiphy into the rdev structure.

While at it, also make it never assign 0 as a cookie
(we consider that invalid in some places), and warn if
we manage to do that for some reason (wrapping is not
likely to happen with a u64.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -4012,7 +4012,6 @@ struct wiphy_iftype_ext_capab {
  *	by the driver in the .connect() callback. The bit position maps to the
  *	attribute indices defined in &enum nl80211_bss_select_attr.
  *
- * @cookie_counter: unique generic cookie counter, used to identify objects.
  * @nan_supported_bands: bands supported by the device in NAN mode, a
  *	bitmap of &enum nl80211_band values.  For instance, for
  *	NL80211_BAND_2GHZ, bit 0 would be set
@@ -4151,8 +4150,6 @@ struct wiphy {
 
 	u32 bss_select_support;
 
-	u64 cookie_counter;
-
 	u8 nan_supported_bands;
 
 	u32 txq_limit;