netbsdaudio: Removed email address from source code.

Not to diminish their contribution, but I'm about to tear this code up
and would rather the bug reports go to the SDL project.

src/audio/netbsd/SDL_netbsdaudio.c

@@ -22,10 +22,7 @@
 
 #ifdef SDL_AUDIO_DRIVER_NETBSD
 
-/*
- * Driver for native NetBSD audio(4).
- * nia@NetBSD.org
- */
+// Driver for native NetBSD audio(4).
 
 #include <errno.h>
 #include <unistd.h>