tslib: bump version to current git head

Due to missing official releases, fetch directly from GitHub
repository. Many bugfixes since 1.0 and all previous patches in
Buildroot are either applied or obsoleted.

Signed-off-by: Daniel Nyström <daniel.nystrom@timeterminal.se>
Acked-by: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Acked-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>