audio: increase soundio binding coverage for running sine-wine example

audio/soundio/ChannelLayout.zig

@@ -0,0 +1,11 @@
+const c = @import("c.zig");
+const intToError = @import("error.zig").intToError;
+const Error = @import("error.zig").Error;
+
+const ChannelLayout = @This();
+
+handle: c.SoundIoChannelLayout,
+
+pub fn channelCount(self: ChannelLayout) i32 {
+    return self.handle.channel_count;
+}