Linux: Update syscall list for 6.16

The generic syscall table has different names for syscalls that take a
timespec64 on 32-bit targets, in that it adds the `_time64` suffix.
Similarly, the `_time32` suffix has been removed.

I'm not sure if the existing logic for determining the proper timespec
struct to use was subtly broken, but it should be a good chance to
finish #4726 - we only have 12 years after all...

As for the changes since 6.11..6.16:

6.11:
 - x86_64 gets `uretprobe`, a syscall to speed up returning BPF probes.
 - Hexagon gets `clone3`, but don't be fooled: it just returns ENOSYS.
6.13:
 - The `*xattr` family of syscalls have been enhanced with new `*xattrat`
   versions, similar to the other file-based `at` calls.
6.15:
 - Atomically create a detached mount tree and set mount options on it.

Finally, this commit also adds the syscall numbers for OpenRISC and maps
it to the `or1k` cpu.

lib/std/os/linux.zig

@@ -144,6 +144,7 @@ pub const SYS = switch (@import("builtin").cpu.arch) {
         else => syscalls.X64,
     },
     .xtensa => syscalls.Xtensa,
+    .or1k => syscalls.OpenRisc,
     else => @compileError("The Zig Standard Library is missing syscall definitions for the target CPU architecture"),
 };