lib/radix-tree: remove unused argument of insert_entries

lib/radix-tree: remove unused argument of insert_entries

insert_entries() doesn't use the 'bool replace' argument, and the function
is only used locally, remove the argument.

The historical context of the unused argument is as follow:

2: commit <3a08cd52c37c79> (radix tree: Remove multiorder support)
  Remove the code related to macro CONFIG_RADIX_TREE_MULTIORDER
to convert to the xArray.
  Without the macro, there is no need to retain the argument.

1: commit <175542f575723e> (radix-tree: add radix_tree_join)
  Add insert_entries(..., bool replace) function, depending on the
macro CONFIG_RADIX_TREE_MULTIORDER definition, the implementation
is different. Notice that the implementation without the macro doesn't
use the argument.

[Matthew Wilcox: add historical context for argument]

Link: https://lkml.kernel.org/r/20220625135324.72574-1-wuchi.zero@gmail.com
Signed-off-by: wuchi <wuchi.zero@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>