pppoe: use timeout_add_sec(9)

[Klemens Nanni]

This is straight forward:  All integer arguments are positive multiples
of `hz', hence it can be safely reduced and the now minimum sleep of one
tick is given already.

One call sleeps a constant amount of
(hz / 50) [ticks] = (hz / 50) / hz [s] = 1 / 50 [s] = 0.02 [s] = 20 [ms]

Runs fine on my APU2's PPPoE link to ISP.
Feedback? OK?

Index: if_pppoe.c
===================================================================
RCS file: /cvs/src/sys/net/if_pppoe.c,v
retrieving revision 1.67
diff -u -p -r1.67 if_pppoe.c
--- if_pppoe.c  19 Feb 2018 08:59:52 -0000      1.67
+++ if_pppoe.c  15 Jun 2019 19:42:37 -0000
@@ -109,8 +109,8 @@ struct pppoetag {
                PPPOE_ADD_16(PTR, SESS);        \
                PPPOE_ADD_16(PTR, LEN)
 
-#define        PPPOE_DISC_TIMEOUT      (hz*5)  /* base for quick timeout 
calculation */
-#define        PPPOE_SLOW_RETRY        (hz*60) /* persistent retry interval */
+#define        PPPOE_DISC_TIMEOUT      5       /* base for quick timeout 
calculation (seconds) */
+#define        PPPOE_SLOW_RETRY        60      /* persistent retry interval 
(seconds) */
 #define        PPPOE_DISC_MAXPADI      4       /* retry PADI four times 
(quickly) */
 #define        PPPOE_DISC_MAXPADR      2       /* retry PADR twice */
 
@@ -579,7 +579,7 @@ breakbreak:
                        PPPOEDEBUG(("%s: failed to send PADR, error=%d\n",
                            sc->sc_sppp.pp_if.if_xname, err));
                }
-               timeout_add(&sc->sc_timeout,
+               timeout_add_sec(&sc->sc_timeout,
                    PPPOE_DISC_TIMEOUT * (1 + sc->sc_padr_retried));
 
                break;
@@ -1086,7 +1086,7 @@ pppoe_timeout(void *arg)
                        PPPOEDEBUG(("%s: failed to transmit PADI, error=%d\n",
                            sc->sc_sppp.pp_if.if_xname, err));
                }
-               timeout_add(&sc->sc_timeout, retry_wait);
+               timeout_add_sec(&sc->sc_timeout, retry_wait);
                splx(x);
 
                break;
@@ -1102,7 +1102,7 @@ pppoe_timeout(void *arg)
                                PPPOEDEBUG(("%s: failed to send PADI, 
error=%d\n",
                                    sc->sc_sppp.pp_if.if_xname, err));
                        }
-                       timeout_add(&sc->sc_timeout,
+                       timeout_add_sec(&sc->sc_timeout,
                            PPPOE_DISC_TIMEOUT * (1 + sc->sc_padi_retried));
                        splx(x);
                        break;
@@ -1112,7 +1112,7 @@ pppoe_timeout(void *arg)
                        PPPOEDEBUG(("%s: failed to send PADR, error=%d\n",
                            sc->sc_sppp.pp_if.if_xname, err));
                }
-               timeout_add(&sc->sc_timeout,
+               timeout_add_sec(&sc->sc_timeout,
                    PPPOE_DISC_TIMEOUT * (1 + sc->sc_padr_retried));
                splx(x);
 
@@ -1146,7 +1146,7 @@ pppoe_connect(struct pppoe_softc *sc)
                PPPOEDEBUG(("%s: failed to send PADI, error=%d\n",
                    sc->sc_sppp.pp_if.if_xname, err));
 
-       timeout_add(&sc->sc_timeout, PPPOE_DISC_TIMEOUT);
+       timeout_add_sec(&sc->sc_timeout, PPPOE_DISC_TIMEOUT);
        splx(x);
 
        return (err);
@@ -1346,7 +1346,7 @@ pppoe_tlf(struct sppp *sp)
         * function and defer disconnecting to the timeout handler.
         */
        sc->sc_state = PPPOE_STATE_CLOSING;
-       timeout_add(&sc->sc_timeout, hz / 50);
+       timeout_add_msec(&sc->sc_timeout, 20);
 }
 
 static void