mesa/sso: Add gl_pipeline_object parameter to _mesa_use_shader_program

mesa/sso: Add gl_pipeline_object parameter to _mesa_use_shader_program

Extend use_shader_program to support a different target. Allow to reuse the
function to update the pipeline state. Note I bypass the flush when target
isn't current. Maybe it would be better to create a new UseProgramStages
driver function

This was originally included in another patch, but it was split out by
Ian Romanick.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>