config: Update clang version to clang-r487747c

* This is the default clang version for Android U release

Change-Id: I6a44012250470eeeb2e0f6993eb4e98308eec390
diff --git a/config/BoardConfigKernel.mk b/config/BoardConfigKernel.mk
index f584046..0cb175c 100644
--- a/config/BoardConfigKernel.mk
+++ b/config/BoardConfigKernel.mk
@@ -90,7 +90,7 @@
     KERNEL_CLANG_VERSION := clang-$(TARGET_KERNEL_CLANG_VERSION)
 else
     # Use the default version of clang if TARGET_KERNEL_CLANG_VERSION hasn't been set by the device config
-    KERNEL_CLANG_VERSION := clang-r450784d
+    KERNEL_CLANG_VERSION := clang-r487747c
 endif
 TARGET_KERNEL_CLANG_PATH ?= $(BUILD_TOP)/prebuilts/clang/host/$(HOST_PREBUILT_TAG)/$(KERNEL_CLANG_VERSION)