fix unused stuff warnings

kernel/dev/termdev.c

@@ -10,7 +10,7 @@
 #include "sysdefs/dev.h"
 
 int32_t termdev_putch(struct Dev *dev, uint8_t *buffer, size_t len, uint64_t pid) {
-  (void)dev;
+  (void)dev; (void)pid;
   kprintf("%.*s", (int)len, (char *)buffer);
   return E_OK;
 }