[libc] Swap order of syscall on chmod (#138427)

We define SYS_fchmodat2 on libc but the syscall is not available on old
kernels, so prefer the SYS_fchmodat version when possible.

NOKEYCHECK=True
GitOrigin-RevId: 230f332cf0139fed88145c9d2dd410c36348f2e4
1 file changed