net: rpl: Change default value for NET_RPL_INIT_LINK_METRIC

Current default value for NET_RPL_INIT_LINK_METRIC is 2, changing it
to 1.

e.g. NET_RPL_MIN_HOP_RANK_INC is 256 and NET_RPL_MC_ETX_DIVISOR is 256.
     Rank calculation for nodes is
     rank_increase = CONFIG_NET_RPL_INIT_LINK_METRIC *
                             NET_RPL_MC_ETX_DIVISOR;

     Which gives 768 for first set of child nodes. It would be good if
     CONFIG_NET_RPL_INIT_LINK_METRIC value is 1 and nodes ranks will be
     245, 512, 768 based on the path they choose.

User can absolutely change their configuration to maintain proper ranks.

Signed-off-by: Ravi kumar Veeramally <[email protected]>

Author: rveerama1

subsys/net/ip/Kconfig.rpl

@@ -195,7 +195,7 @@ config	NET_RPL_MIN_HOP_RANK_INC
 config	NET_RPL_INIT_LINK_METRIC
 	int "Initial link metric"
 	depends on NET_RPL
-	default 2
+	default 1
 	help
 	Initial metric attributed to a link when the ETX is unknown.