ARM64: vdso32: Hardcode toolchain target

Fixes the following error when building with clang r530567:
error: version 'kernel' in target triple 'arm-unknown-linux-androidkernel' is invalid

Change-Id: I5a2d27bf0e8a22b2fe752c64efc0cc91c790b5f0

Author: luk1337

arch/arm64/Makefile

@@ -65,7 +65,7 @@ ifeq ($(CONFIG_COMPAT_VDSO), y)
     $(error CROSS_COMPILE_ARM32 not defined or empty, the compat vDSO will not be built)
   else ifeq ($(cc-name),clang)
     export CLANG_TRIPLE_ARM32 ?= $(CROSS_COMPILE_ARM32)
-    export CLANG_TARGET_ARM32 := --target=$(notdir $(CLANG_TRIPLE_ARM32:%-=%))
+    export CLANG_TARGET_ARM32 := --target=arm-linux-gnueabi
     export CONFIG_VDSO32 := y
     vdso32 := -DCONFIG_VDSO32=1
   else ifeq ($(shell which $(CROSS_COMPILE_ARM32)$(cc-name) 2> /dev/null),)