kernel: use mpaland printf

kernel-src/io/logging.c

@@ -0,0 +1,14 @@
+static void nohook(char c) {
+
+}
+
+static void (*hook)(char) = nohook;
+
+// hook used by mpaland printf
+void _putchar(char c) {
+	hook(c);
+}
+
+void logging_sethook(void (*fun)(char)) {
+	hook = fun;
+}