!729 add mips arch support

Merge pull request !729 from wicom/master

musl_config.gni

@@ -10,6 +10,8 @@ declare_args() {
     musl_arch = "aarch64"
   } else if (current_cpu == "x86_64" || current_cpu == "x64") {
     musl_arch = "x86_64"
+  } else if (current_cpu == "mipsel") {
+    musl_arch = "mipsel"
   }
   # musl_root = "$root_out_dir/obj/third_party/musl"
   # musl_sub_arch = ""