Modify BPF descriptor assertions to assert Giant when a BPF descriptor

lock is asserted and running non-MPSAFE.

sys/net/bpfdesc.h

@@ -102,7 +102,10 @@ struct bpf_d {
 
 #define BPFD_LOCK(bd)		mtx_lock(&(bd)->bd_mtx)
 #define BPFD_UNLOCK(bd)		mtx_unlock(&(bd)->bd_mtx)
-#define BPFD_LOCK_ASSERT(bd)	mtx_assert(&(bd)->bd_mtx, MA_OWNED)
+#define BPFD_LOCK_ASSERT(bd)	do {				\
+	mtx_assert(&(bd)->bd_mtx, MA_OWNED);			\
+	NET_ASSERT_GIANT();					\
+} while (0)
 
 /* Test whether a BPF is ready for read(). */
 #define	bpf_ready(bd)						 \