Revert upstream commit 2d94f7dea9c73ef3c116a0ddc722724578a860fe:

https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=2d94f7dea9c73ef3c116a0ddc722724578a860fe

Redundant .machine directive overrides necessary CPU flags passed to
as(1), which results in mis-assemble codes to 40[35], for example.

Index: external/gpl3/gcc/dist/gcc/config/rs6000/rs6000.c
===================================================================
RCS file: /home/netbsd/src/external/gpl3/gcc/dist/gcc/config/rs6000/rs6000.c,v
retrieving revision 1.24
diff -p -u -r1.24 rs6000.c
--- external/gpl3/gcc/dist/gcc/config/rs6000/rs6000.c	12 Apr 2021 07:23:06 -0000	1.24
+++ external/gpl3/gcc/dist/gcc/config/rs6000/rs6000.c	13 Apr 2021 02:35:57 -0000
@@ -5644,7 +5644,9 @@ rs6000_file_start (void)
 
 #ifdef USING_ELFOS_H
   rs6000_machine = rs6000_machine_from_flags ();
-  emit_asm_machine ();
+  if (!(rs6000_default_cpu && rs6000_default_cpu[0])
+	&& !global_options_set.x_rs6000_cpu_index)
+    emit_asm_machine ();
 #endif
 
   if (DEFAULT_ABI == ABI_ELFv2)