Remove unneeded #include

Unneeded since commit d72731a704.

Discussion: https://www.postgresql.org/message-id/391abe21-413e-4d91-a650-b663af49500c@iki.fi

src/include/storage/buf_internals.h

@@ -20,7 +20,6 @@
 #include "storage/buf.h"
 #include "storage/bufmgr.h"
 #include "storage/condition_variable.h"
-#include "storage/latch.h"
 #include "storage/lwlock.h"
 #include "storage/shmem.h"
 #include "storage/smgr.h"