Steady laminar flow between two fluid layers is often inherently unstable [Rayleigh 1894, The Theory of Sound]. When the boundary is sharp and the difference in speed is significant, this instability can create audible noise. This is the core mechanism of sound production in both whistling with the lips and some instruments like the flute and flue organ pipes.
The other feature of these sounds is resonance from a cavity and sometimes a feedback of the resonance to the driving oscillation. In instruments, the feedback is enhanced by a sharp mechanical edge in the flow stream (an edge in the mechanical windway in pipes and recorders, and the opposite edge of the mouthpiece hole in a flute), so that the oscillation alternates to opposing sides of the edge.
It's interesting that in some configurations of whistling one can transition from no sound to sound by: 1) blowing harder (enhancing the speed difference between the outgoing and stationary air); or 2) introducing a knife edge perpendicular to the airflow (reducing the width of the boundary between the two flow regions).
To answer your exact question: steady flow in air can produce a sound. Whether it does depends on the boundary between the flowing and stationary air (and because it's unstable, whether you now call this "steady" is a bit a question of semantics).