batman-adv: Avoid relation operator comparison with bool

commit 785ea1144182 ("batman-adv: Distributed ARP Table - create DHT helper
functions") introduced a return check of batadv_compare_eth which uses a
boolean return value since commit 16af73458aca ("batman-adv: main,
batadv_compare_eth return bool"). A relational (<, >, <= or >=) operator
is not the right one for such a check.

Reported-by: David Binderman <[e-mail]>
Signed-off-by: Sven Eckelmann <[e-mail]>
Acked-by: Antonio Quartulli <[e-mail]>
Signed-off-by: Simon Wunderlich <[e-mail]>

net/batman-adv/distributed-arp-table.c

···
 	 * the one with the lowest address
 	 */
 	if (tmp_max == max && max_orig_node &&
-	    batadv_compare_eth(candidate->orig, max_orig_node->orig) > 0)
+	    batadv_compare_eth(candidate->orig, max_orig_node->orig))
 		goto out;
 
 	ret = true;