util/hashx: move from sha256x (#5388)

cmd/tailscaled/depaware.txt

@@ -273,13 +273,13 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/util/dnsname                                   from tailscale.com/hostinfo+
   LW    tailscale.com/util/endian                                    from tailscale.com/net/dns+
         tailscale.com/util/groupmember                               from tailscale.com/ipn/ipnserver
+     💣 tailscale.com/util/hashx                                     from tailscale.com/util/deephash
         tailscale.com/util/lineread                                  from tailscale.com/hostinfo+
         tailscale.com/util/mak                                       from tailscale.com/control/controlclient+
         tailscale.com/util/multierr                                  from tailscale.com/control/controlclient+
         tailscale.com/util/osshare                                   from tailscale.com/ipn/ipnlocal+
         tailscale.com/util/pidowner                                  from tailscale.com/ipn/ipnserver
         tailscale.com/util/racebuild                                 from tailscale.com/logpolicy
-     💣 tailscale.com/util/sha256x                                   from tailscale.com/util/deephash
         tailscale.com/util/singleflight                              from tailscale.com/control/controlclient+
    L    tailscale.com/util/strs                                      from tailscale.com/hostinfo
         tailscale.com/util/systemd                                   from tailscale.com/control/controlclient+

util/deephash/deephash.go

@@ -34,7 +34,7 @@ import (
 	"time"
 	"unsafe"
 
-	hashx "tailscale.com/util/sha256x"
+	"tailscale.com/util/hashx"
 )
 
 // There is much overlap between the theory of serialization and hashing.