net: trickle: Misc changes

* Fix the indentation which was caused by uint32_t -> u8_t changes.
* Make sure there is no unused variable warning if debugging is
  enabled but debug level is low.
* Add assert that checks that Imax_abs is > 0 which it should be.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
diff --git a/include/net/trickle.h b/include/net/trickle.h
index 5a318f5..72bf580 100644
--- a/include/net/trickle.h
+++ b/include/net/trickle.h
@@ -36,13 +36,13 @@
 struct net_trickle {
 	u32_t Imin;		/* Min interval size in ms */
 	u8_t Imax;		/* Max number of doublings */
-	u8_t k;		/* Redundancy constant */
+	u8_t k;			/* Redundancy constant */
 
 	u32_t I;		/* Current interval size */
-	u32_t Istart;	/* Start of the interval in ms */
-	u8_t c;		/* Consistency counter */
+	u32_t Istart;		/* Start of the interval in ms */
+	u8_t c;			/* Consistency counter */
 
-	u32_t Imax_abs;	/* Max interval size in ms (not doublings)
+	u32_t Imax_abs;		/* Max interval size in ms (not doublings)
 				 */
 
 	struct k_delayed_work timer;
diff --git a/subsys/net/ip/trickle.c b/subsys/net/ip/trickle.c
index ad7405b..551c1f5 100644
--- a/subsys/net/ip/trickle.c
+++ b/subsys/net/ip/trickle.c
@@ -56,7 +56,7 @@
 						   timer);
 	u32_t rand_time;
 
-#if defined(CONFIG_NET_DEBUG_TRICKLE)
+#if defined(CONFIG_NET_DEBUG_TRICKLE) && (CONFIG_SYS_LOG_NET_LEVEL > 2)
 	u32_t last_end = get_end(trickle);
 #endif
 
@@ -163,6 +163,8 @@
 	trickle->Imax_abs = Imin << Imax;
 	trickle->k = k;
 
+	NET_ASSERT(trickle->Imax_abs);
+
 	NET_DBG("Imin %d Imax %u k %u Imax_abs %d",
 		trickle->Imin, trickle->Imax, trickle->k,
 		trickle->Imax_abs);