sdt: Enable on 32-bit powerpc and powerpc64le

[markj]

Summary

The former because we expect it will work, and the latter because it was
omitted by mistake.

[adrian]

works for me!

tested: power8 S822LC, powerNV (160 threads)

[jhibbits]

Please MFC this to 15 and 14 as well.

[markj]

Is either of you able to test 32-bit powerpc? Just something like dtrace -n 'sched:::on-cpu {stack();}' should be good enough. If not I'll try to test when I get a chance.

[adrian]

sigh, turns out we need to fix something in sdt_machdep.h first:

--------------------------------------------------------------
>>> stage 3.1: building everything
--------------------------------------------------------------
/home/adrian/work/freebsd/head/freebsd-src-ppc64/sys/powerpc/powerpc/sdt_machdep.c:41:16: error: format specifies type 'unsigned long' but the argument has type 'uintptr_t' (aka 'unsigned int') [-Werror,-Wformat]
   40 |             ("%s: invalid tracepoint %#lx -> %#lx",
      |                                      ~~~~
      |                                      %#x
   41 |             __func__, patchpoint, target));
      |                       ^~~~~~~~~~
/home/adrian/work/freebsd/head/freebsd-src-ppc64/sys/sys/kassert.h:146:17: note: expanded from macro 'KASSERT'
  146 |                 kassert_panic msg;

This happens when building powerpc;powerpc + GENERIC, but not powerpc:powerpc64 + GENERIC64

[markj]

Fix the build on 32-bit powerpc

[markj]

In D54814#1256550, @adrian wrote:

sigh, turns out we need to fix something in sdt_machdep.h first:

Woops, I thought I had build-tested this...