ppc: do not redefine CPUPPCState

Just include the file that is supposed to bring it in.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

include/hw/ppc/fdt.h

@@ -11,8 +11,7 @@
 #define PPC_FDT_H
 
 #include "qemu/error-report.h"
-
-typedef struct CPUPPCState CPUPPCState;
+#include "target-ppc/cpu-qom.h"
 
 #define _FDT(exp)                                                  \
     do {                                                           \