radix_tree: tag all internal tree nodes as indirect pointers

radix_tree: tag all internal tree nodes as indirect pointers

Set the 'indirect_ptr' bit on all the pointers to internal nodes, not
just on the root node.  This enables the following patches to support
multi-order entries in the radix tree.  This patch is split out for ease
of bisection.

Signed-off-by: Matthew Wilcox <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Hugh Dickins <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>