FreeBSD/src c90baf6 (r320403)sys/arm64/include atomic.h

Some of the atomic_clear_* functions were incorrectly defined to be an
atomic add. Correct these, fixing a NULL-pointer dereference in netgraph.

PR:             220273
MFC after:      3 days
Sponsored by:   DARPA, AFRL
DeltaFile
+4-3sys/arm64/include/atomic.h
+4-31 files

UnifiedSplitRaw