mac80211_hwsim: use DEFINE_IDA

This is preferred to opencoding an IDA_INIT.

Link: http://lkml.kernel.org/r/20180313132639.17387-2-willy@infradead.orgSigned-off-by: NMatthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/net/wireless/mac80211_hwsim.c

@@ -253,7 +253,7 @@ static inline void hwsim_clear_chanctx_magic(struct ieee80211_chanctx_conf *c)
 
 static unsigned int hwsim_net_id;
 
-static struct ida hwsim_netgroup_ida = IDA_INIT;
+static DEFINE_IDA(hwsim_netgroup_ida);
 
 struct hwsim_net {
 	int netgroup;