Clean up Versions file

Clean up Versions file

The entries in the current Versions file don't work as expected.
Since the first ALSA_0.9 has already snd_* global definitions, all
the rest are simply ignored.  Some symbols (e.g. snd_hw_params_*)
indeed work because they have explicit symver definitions, but
ALSA_0.9.6 and later are all superfluous.

This patch clean up these useless entries.  Also, the patch restricts
the matching patterns for _snd_* and __snd_* entries to reduce the
unneeded export symbols.