Revert "r600g: SQUASH fix null-deref on binding NULL rasterizer cso"

This reverts commit 807e39ea1d465b09e6362ca50b0745c74fb48fe9.
Revert "r600g: add support for disabling viewport and clipping"

This reverts commit 78f04147bc652145600fe246b2b0e99d33bd930a.
gallium,r600g: use TGSI_PROPERTY to disable viewport and clipping

SEPARATEME.
nine: set VS_WINDOW_SPACE_POSITION TGSI property

TODO: Remove viewport hack when I fixed up nouveau.