Temporarily changing vc-intrinsics branch from master to dpcpp_staging because

that branch contains fixes related to upstream LLVM commit
b2ee408 which have broken sycl-web builds.

Author: Georgios Rokos

llvm/lib/SYCLLowerIR/CMakeLists.txt

@@ -14,7 +14,7 @@ if (NOT TARGET LLVMGenXIntrinsics)
   if (NOT DEFINED LLVMGenXIntrinsics_SOURCE_DIR)
     message(STATUS "vc-intrinsics are missing. Will try to download them from github.com")
 
-    set( LLVMGenXIntrinsics_GIT_TAG b1db3e55bac23670be4ffbd0da85a9fd0110f593 )
+    set( LLVMGenXIntrinsics_GIT_TAG dpcpp_staging )
 
     include(FetchContent)
     FetchContent_Declare(vc-intrinsics