Inconsistent atomic vs non-atomic access to wg_packet::p_state

Summary

p_state annotated /* atomic */ but plain store at :508(UNCRYPTED)/:532(DEAD) and plain read at :547 vs atomic_store_rel at :1872/:1938 and atomic_load_acq at :2004/:2052. x86 TSO: benign. Weak-order: transient state inconsistency.