alsa-utils/Config.in: move comment to top, to fix nesting of config options

To allow proper nesting of suboptions of a package, the suboptions should
come directly after the main option, and cannot be interleaved with a
comment.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>