[Tizen] Remove Tizen 2.x-specific patches and code paths in the spec.

Now that we have finally moved away from Tizen 2, we can at last simplify
our spec file a bit and remove some patches that are not needed when
building for Tizen 3.
Merge pull request #1586 from rakuco/remove-tizen2-paths-in-spec

[Tizen] Remove Tizen 2.x-specific patches and code paths in the spec.