cpu-all.h: fix cpu_get_real_ticks() #ifdef

Reported-by: Hervé Poussineau <hpoussin@reactos.org>

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/cpu-all.h b/cpu-all.h
index e214374..57b69f8 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -1017,7 +1017,8 @@
 #endif
 }
 
-#elif (defined(__mips_isa_rev) && __mips_isa_rev >= 2) || defined(__linux__)
+#elif defined(__mips__) && \
+      ((defined(__mips_isa_rev) && __mips_isa_rev >= 2) || defined(__linux__))
 /*
  * binutils wants to use rdhwr only on mips32r2
  * but as linux kernel emulate it, it's fine