Move mips64 target to clang by default.

Bug: 23163853
Change-Id: Ia3d449f908b09ce95b3de246c8c699d171dcbaa3
diff --git a/target/board/generic_mips64/BoardConfig.mk b/target/board/generic_mips64/BoardConfig.mk
index 8e8a68b..d5430cd 100644
--- a/target/board/generic_mips64/BoardConfig.mk
+++ b/target/board/generic_mips64/BoardConfig.mk
@@ -75,3 +75,5 @@
 BOARD_SEPOLICY_DIRS += build/target/board/generic/sepolicy
 
 DEX_PREOPT_DEFAULT := nostripping
+
+USE_CLANG_PLATFORM_BUILD := true