ci/windows: Strip misleading release/15.x

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37210>

.gitlab-ci/windows/mesa_deps_build.ps1

@@ -56,7 +56,7 @@ if (!$buildstatus) {
 }
 
 Get-Date
-Write-Host "Cloning LLVM release/15.x"
+Write-Host "Cloning LLVM"
 git clone -b llvmorg-19.1.6 --depth=1 https://github.com/llvm/llvm-project deps/llvm-project
 if (!$?) {
   Write-Host "Failed to clone LLVM repository"