Switch to clang-2658975.

Bug: http://b/27482631

This fixes an issue where krait compiles were not passing the proper
flags to the assembler when -no-integrated-as is used. This was
preventing ART from switching to clang in some cases.

(cherry picked from commit c503d8ef5826bd1c79dc223ceba614532527a8c9)

Change-Id: I4a0efb78f37fee73bf61841f0347328b8f61c192
diff --git a/core/clang/versions.mk b/core/clang/versions.mk
index 96872c2..f80d6b9 100644
--- a/core/clang/versions.mk
+++ b/core/clang/versions.mk
@@ -1,5 +1,5 @@
 ## Clang/LLVM release versions.
 
 LLVM_RELEASE_VERSION := 3.8
-LLVM_PREBUILTS_VERSION ?= clang-2629532
+LLVM_PREBUILTS_VERSION ?= clang-2658975
 LLVM_PREBUILTS_BASE ?= prebuilts/clang/host