docs: fix broken documentation links

Mostly due to x86 and acpi conversion, several documentation
links are still pointing to the old file. Fix them.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
Reviewed-by: Sven Van Asbroeck <TheSven73@gmail.com>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/mm/Kconfig b/mm/Kconfig
index ee8d1f3..6e5fb81 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -165,7 +165,7 @@
 	  onlining policy (/sys/devices/system/memory/auto_online_blocks) which
 	  determines what happens to newly added memory regions. Policy setting
 	  can always be changed at runtime.
-	  See Documentation/memory-hotplug.txt for more information.
+	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
 
 	  Say Y here if you want all hot-plugged memory blocks to appear in
 	  'online' state by default.