start: LLVM 17 regression compiling `_start` for `riscv64-linux`

```zig
pub fn main() void {}
```
```
$ zig build-exe repro.zig -target riscv64-linux
LLVM Emit Object... error: invalid operand in inline asm: ' li s0, 0
 li ra, 0
 sd sp, ${0}
 andi sp, sp, -16
 tail ${1}@plt'
```
upstream: llvm/llvm-project#64656