linux: remove powerpc device-tree parsing

It's disabled by default since 6608c48 in 2.1.
No problem reported, let's remove it entirely.

This code was contributed by Alexey Kardashevskiy from IBM in 2010/09 (hwloc 1.1)
when the Linux kernel on powerpc didn't use the device-tree to discover
cores/caches and expose them in sysfs. This was fixed in 2.6.29 in 2009
(93197a36a9c16a85fb24cf5a8639f7bf9af838a3) which is deployed everywhere now.

I've seen some POWER9 with buggy package information,
but this is not covered by our DT code.

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>

Author: bgoglin

NEWS

@@ -29,6 +29,8 @@ Version 2.3.0
   + Add a ROCm SMI backend and a hwloc/rsmi.h helper file for getting
     the locality of AMD GPUs, now exposed as "rsmi" OS devices.
     Thanks to Mike Li.
+  + Remove POWER device-tree-based topology on Linux,
+    (it was disabled by default since 2.1).
 * Tools
   + Command-line options for specifying flags now understand comma-separated
     lists of flag names (substrings).