[patch] install missing rs6000 header, needed to build plugins

[Matthias Klose]

This installs the rs6000-cpus.def file for powerpc targets (included by
default64.h), which is needed to build plugins on powerpc64* targets.

Ok for the trunk, and the 5 branch? Tested with a build and installation.

Matthias

        PR target/66840
        * config/rs6000/t-rs6000 (TM_H): Add rs6000-cpus.def.

--- gcc/config/rs6000/t-rs6000
+++ gcc/config/rs6000/t-rs6000
@@ -19,6 +19,7 @@
 # <http://www.gnu.org/licenses/>.
 
 TM_H += $(srcdir)/config/rs6000/rs6000-builtin.def
+TM_H += $(srcdir)/config/rs6000/rs6000-cpus.def
 
 rs6000-c.o: $(srcdir)/config/rs6000/rs6000-c.c
        $(COMPILE) $<