Correct comment

src/sdl/mixer_sound.c

@@ -1251,7 +1251,7 @@ boolean I_LoadSong(char *data, size_t len)
 
 #ifdef HAVE_OPENMPT
 	/*
-		If the size of the data to be checked is bigger than the recommended size (> 2048)
+		If the size of the data to be checked is bigger than the recommended size (> 2048 bytes)
 		Let's just set the probe size to the recommended size
 		Otherwise let's give it the full data size
 	*/