Linux: removed the duplicated linking of libudev

Existence checking and linking of libudev is already carried out by means of
pkgconfig.

Change-Id: I5233ab2ce7ed342d95e8ba646b4024c8ad6b8a78
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>
Reviewed-by: Laszlo Papp <lpapp@kde.org>