Switch x86 default compiler to multilib version

Switch from gcc-4.7 32-bit only to gcc-4.7 multilib (32/x32/64) compiler.
Tested x86 image build on Linux and Darwin.

This bionic patch is required:
https://android-review.googlesource.com/#/c/64183

Change-Id: Ifc2c6c5d6a4a1b71a00a87af072bb7f67b1c284d
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>
diff --git a/core/llvm_config.mk b/core/llvm_config.mk
index 0fe9f93..c679e42 100644
--- a/core/llvm_config.mk
+++ b/core/llvm_config.mk
@@ -72,11 +72,11 @@
   CLANG_CONFIG_EXTRA_ASFLAGS += \
     -target i686-linux-android \
     -nostdlibinc \
-    -B$(TARGET_TOOLCHAIN_ROOT)/i686-linux-android/bin
+    -B$(TARGET_TOOLCHAIN_ROOT)/x86_64-linux-android/bin
   CLANG_CONFIG_EXTRA_CFLAGS += $(CLANG_CONFIG_EXTRA_ASFLAGS)
   CLANG_CONFIG_EXTRA_LDFLAGS += \
     -target i686-linux-android \
-    -B$(TARGET_TOOLCHAIN_ROOT)/i686-linux-android/bin
+    -B$(TARGET_TOOLCHAIN_ROOT)/x86_64-linux-android/bin
   CLANG_CONFIG_UNKNOWN_CFLAGS += \
     -finline-limit=300 \
     -fno-inline-functions-called-once \