wlantest: Add preliminary infrastructure for injecting frames

This adds new commands for wlantest_cli to request wlantest to
inject frames. This version can only send out Authentication
frames and unprotected SA Query Request frames, but there is
now place to add more frames and encryption with future commits.

src/utils/common.h

@@ -459,6 +459,11 @@ static inline int is_zero_ether_addr(const u8 *a)
 	return !(a[0] | a[1] | a[2] | a[3] | a[4] | a[5]);
 }
 
+static inline int is_broadcast_ether_addr(const u8 *a)
+{
+	return (a[0] & a[1] & a[2] & a[3] & a[4] & a[5]) == 0xff;
+}
+
 #include "wpa_debug.h"