Merge pull request #568 from ojeda/ppc-code-model

rust: fix PowerPC machine model typo & value

Author: ojeda

arch/powerpc/rust/target.json

@@ -1,6 +1,6 @@
 {
   "arch": "powerpc64",
-  "code-mode": "kernel",
+  "code-model": "large",
   "cpu": "ppc64le",
   "data-layout": "e-m:e-i64:64-n32:64",
   "env": "gnu",