[AD] Setup setting wrong alsa_numfrags

[Stepan Roh <stepan@xxxxxxxxxx>]

Setup writes alsa_numfrags=2 into the allegro.cfg. This produces terrible
sound. Default value used in autodetection in unix/alsa.c is 16, so it
should be changed that way. Row 231 in setup.c should be changed from

   { "alsa_numfrags",      param_int,     "",      "2",        NULL,

to

   { "alsa_numfrags",      param_int,     "",      "16",        NULL,

or better yet to

   { "alsa_numfrags",      param_int,     "",      "",        NULL,

Have a nice day.

Stepan Roh