base-files: fix ucidef_set_interface() protocol selection

The previous refactoring of ucidef_set_interface() removed the protocol
selection heuristic which breaks the networking defaults for the majority
of boards.

Re-add the protocol selection and rename two bad "proto" references to
the expected "protocol" value.

Fixes: 85048a9c1f ("base-files: rework _ucidef_set_interface to be more generic")
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

package/base-files/files/lib/functions/uci-defaults.sh

@@ -28,24 +28,30 @@ json_select_object() {
 }
 
 ucidef_set_interface() {
-	local network=$1
+	local network=$1; shift
 
 	[ -z "$network" ] && return
 
 	json_select_object network
 	json_select_object "$network"
-	shift
 
 	while [ -n "$1" ]; do
-		local opt="$1"
-		local val="$2"
-		shift; shift;
+		local opt=$1; shift
+		local val=$1; shift
 
 		[ -n "$opt" -a -n "$val" ] || break
 
 		json_add_string "$opt" "$val"
 	done
 
+	if ! json_is_a protocol string; then
+		case "$network" in
+			lan) json_add_string protocol static ;;
+			wan) json_add_string protocol dhcp ;;
+			*) json_add_string protocol none ;;
+		esac
+	fi
+
 	json_select ..
 	json_select ..
 }