graphics/vulkan-loader: unbreak on -CURRENT i386 after 14c23983083d

FAILED: loader/CMakeFiles/vulkan.dir/unknown_ext_chain_gas_x86.S.o
Assertion failed: (Type == RT32_32), function getRelocType32, file /usr/local/poudriere/jails/main-i386/usr/src/contrib/llvm-project/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp, line 269.
[...]
FreeBSD clang version 13.0.0 (git@github.com:llvm/llvm-project.git llvmorg-13.0.0-0-gd7b669b3a303)
Target: i386-unknown-freebsd14.0
Thread model: posix
InstalledDir: /usr/bin

Reported by: pkg-fallout