glsl: Add EXT_texture_array support for geometry shaders.

glsl: Add EXT_texture_array support for geometry shaders.

We can't just use a ".glsl" file since the Lod variants are only
available in vertex and geometry shaders, while the bias variants are
only available in the fragment shader.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>