uprobes: Simplify the usage of uprobe->pending_list

uprobes: Simplify the usage of uprobe->pending_list

uprobe->pending_list is only used to create the temporary list,
it has no meaning after we drop uprobes_mmap_hash(inode).

No need to initialize this node or remove it from tmp_list, and
we can use list_for_each_entry().

Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Anton Arapov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Srikar Dronamraju <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>