update LLVM submodule to make libunwind work on SGX

diff --git a/src/llvm-project b/src/llvm-project
index 2a2ea6b49e79325e0d10d33fac2b10ea3bebcc7c..a1232c451fc27173f8718e05d174b2503ca0b607 160000 (submodule)
--- a/src/llvm-project
+++ b/src/llvm-project
@@ -1 +1 @@
-Subproject commit 2a2ea6b49e79325e0d10d33fac2b10ea3bebcc7c
+Subproject commit a1232c451fc27173f8718e05d174b2503ca0b607