uprobes: Kill uprobe_consumer->filter()

uprobe_consumer->filter() is pointless in its current form, kill it.

We will add it back, but with the different signature/semantics. Perhaps
we will even re-introduce the callsite in handler_chain(), but not to
just skip uc->handler().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

kernel/trace/trace_uprobe.c

@@ -550,7 +550,6 @@ static int probe_event_enable(struct trace_uprobe *tu, int flag)
 		return -EINTR;
 
 	utc->cons.handler = uprobe_dispatcher;
-	utc->cons.filter = NULL;
 	ret = uprobe_register(tu->inode, tu->offset, &utc->cons);
 	if (ret) {
 		kfree(utc);