Fixes for Skyrim and FO4 shaders

[Candoran2]

Problems:

• For Skyrim models without textures and with tangent space normals, vertex normals were not applied.
• FO4 meshes shading was incorrect.

Solutions:

• Adjust if-block to also initiate normal to vertex normal when using a tangent space mesh without textures (and not just when using model space normals). - done by Ousnius.
• Reconstitute the missing blue channel for the normal map before converting the normal from tangent space to view space.