mm, x86, ptrace, bts: defer branch trace stopping, remove dead code

Remove the unused free_locked_buffer() API.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

mm/mlock.c

@@ -671,9 +671,3 @@ void refund_locked_buffer_memory(struct mm_struct *mm, size_t size)
 
 	up_write(&mm->mmap_sem);
 }
-
-void free_locked_buffer(void *buffer, size_t size)
-{
-	refund_locked_buffer_memory(current->mm, size);
-	kfree(buffer);
-}