mesa: remove unnecessary 'sort by year' for the GL extensions

mesa: remove unnecessary 'sort by year' for the GL extensions

The sorting was originally added to work around broken games (comment
says Quake3 demo) that were copying the extensions list into small
buffer.

Sorting does not solve the problem, since we'll still overflow and cause
corruption/crash.

Better workaround is to actually trim the string ... as done with a
later commit which introduces the MESA_EXTENSION_MAX_YEAR env. variable.

Side note: On my machine, the existing sorting makes no changes to the
extensions string.

Cc: Jose Fonseca <jfonseca@vmware.com>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Brian Paul <brianp@vmware.com>