t9write: Fix Greek character sets

Include Greek alphabet in the character sets
for Greek language.

Change-Id: I68184cf1d162db0fb9d73c9cb8ce0e062ea1ec20
Reviewed-by: Jarkko Koivikko <jarkko.koivikko@code-q.fi>
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>