io_uring: remove NOP queue on nonblocking mode

This is not needed, and the reason it was there was probably related to
the earlier commit.

src/aio/IoUring.zig

@@ -106,26 +106,15 @@ pub fn queue(self: *@This(), comptime len: u16, work: anytype, cb: ?aio.Dynamic.
     self.pending += len;
 }
 
-pub const NOP = std.math.maxInt(u64);
-
 /// TODO: give options perhaps? More customization?
 pub fn complete(self: *@This(), mode: aio.Dynamic.CompletionMode, cb: ?aio.Dynamic.CompletionCallback) aio.Error!aio.CompletionResult {
     if (self.pending == 0) return .{};
 
-    if (mode == .nonblocking) {
-        var last = &self.io.sq.sqes[self.io.sq.sqe_tail & self.io.sq.mask];
-        _ = try self.io.nop(NOP);
-        // it is error to have these on the last operation
-        last.flags &= ~@as(u8, std.os.linux.IOSQE_IO_LINK | std.os.linux.IOSQE_IO_HARDLINK);
-        self.pending += 1;
-    }
-
     _ = try uring_submit(&self.io);
 
     var result: aio.CompletionResult = .{};
-    const n = try uring_copy_cqes(&self.io, self.cqes, 1);
+    const n = try uring_copy_cqes(&self.io, self.cqes, if (mode == .nonblocking) 0 else 1);
     for (self.cqes[0..n]) |*cqe| {
-        if (cqe.user_data == NOP) continue;
         const uop = self.ops.get(@intCast(cqe.user_data)).*;
         var failed: bool = false;
         switch (uop) {
@@ -139,7 +128,7 @@ pub fn complete(self: *@This(), mode: aio.Dynamic.CompletionMode, cb: ?aio.Dynam
     }
 
     self.pending -= n;
-    result.num_completed = n - @intFromBool(mode == .nonblocking);
+    result.num_completed = n;
     return result;
 }