Utilities: Use lround() instead of casting round() to long

And one case where we previously cast to int, since the extra precision
does not matter.

Userland/Utilities/adjtime.cpp

@@ -21,7 +21,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     args_parser.parse(arguments);
 
     if (delta.has_value()) {
-        long delta_us = static_cast<long>(round(*delta * 1'000'000));
+        long delta_us = lround(*delta * 1'000'000);
         timeval delta_timeval;
         delta_timeval.tv_sec = delta_us / 1'000'000;
         delta_timeval.tv_usec = delta_us % 1'000'000;

Userland/Utilities/asctl.cpp

@@ -69,7 +69,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
         for (auto to_print : values_to_print) {
             switch (to_print) {
             case AudioVariable::Volume: {
-                auto volume = static_cast<int>(round(audio_client->get_main_mix_volume() * 100));
+                auto volume = lround(audio_client->get_main_mix_volume() * 100);
                 if (human_mode)
                     outln("Volume: {}%", volume);
                 else

Userland/Utilities/ntpquery.cpp

@@ -306,7 +306,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     outln("Offset: {}", offset_s);
 
     if (adjust_time) {
-        long delta_us = static_cast<long>(round(offset_s * 1'000'000));
+        long delta_us = lround(offset_s * 1'000'000);
         timeval delta_timeval;
         delta_timeval.tv_sec = delta_us / 1'000'000;
         delta_timeval.tv_usec = delta_us % 1'000'000;