[kernel] Remove placement-new declaration from memory.h.cog

Finishing the trend of using `#include <new>` to define new, get rid of
the last bits of custom-declared operator new.

src/kernel/logger.cpp

@@ -1,3 +1,4 @@
+#include <new>
 #include <string.h>
 
 #include <util/no_construct.h>