pvr: stop restricting the compiler to the Sascha Willems triangle demo

pvr: stop restricting the compiler to the Sascha Willems triangle demo

Do this by removing the compatibility table and only using hard coded shaders
when present. The hard coded shaders, along with the hard coding framework
itself, can be dropped once the compiler is capable of compiling the hard coded
shaders. In the meantime we don't want to risk regressing things that we know
work because we temporarily can't test them.

This restriction is being dropped now as the new compiler framework has been
merged and we want to make use of it so it can be developed further.

Signed-off-by: Frank Binns <frank.binns@imgtec.com>
Reviewed-by: Karmjit Mahil <Karmjit.Mahil@imgtec.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21495>