logging: make term and printf smp safe

kernel-src/io/logging.c

@@ -1,3 +1,7 @@
+#include <mutex.h>
+
+mutex_t printf_mutex;
+
 static void nohook(char c) {
 
 }
@@ -12,3 +16,7 @@ void _putchar(char c) {
 void logging_sethook(void (*fun)(char)) {
 	hook = fun;
 }
+
+void logging_init() {
+	MUTEX_INIT(&printf_mutex);
+}