pipe-loader: wire up the 'static' sw pipe-loader

pipe-loader: wire up the 'static' sw pipe-loader

Analogous to previous commit with a small catch.

As the sw inline helpers are mere wrappers, and the screen <> winsys
split is more prominent (with the latter not being part of the final
pipe-driver), things will just work.

v2: rebase on top of earlier 'consolitate teardown' changes

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Acked-by: Rob Clark <robclark@freedesktop.org>