MIPS64: Add clang compile flags for MIPS64r6

build/config/android/BUILD.gn

Index: build/config/android/BUILD.gn
diff --git a/build/config/android/BUILD.gn b/build/config/android/BUILD.gn
index 883b82ffd556614636b586fe9a12a019921c4b1c..b966d8cd84d269d589c113ee386bba36d2ccf2ff 100644
--- a/build/config/android/BUILD.gn
+++ b/build/config/android/BUILD.gn
@@ -27,10 +27,10 @@ config("compiler") {
     rebased_android_toolchain_root =
         rebase_path(android_toolchain_root, root_build_dir)
     assert(rebased_android_toolchain_root != "")  # Mark as used.
-    if (current_cpu == "mipsel") {
+    if (current_cpu == "mipsel" || current_cpu == "mips64el") {
       cflags += [
         # TODO(gordanac) Enable integrated-as.
-        "-no-integrated-as",
+        "-fno-integrated-as",
         "-B${rebased_android_toolchain_root}/bin",  # Else /usr/bin/as gets picked up.
       ]
     }