r300: Set more shadow sampler lowering in precompiles.

Just a simple fix for the compile errors reported in #6771 the errors are harmless because the precompiled variants are never used, so this is just shader-db fix (to report some reasonable stats).

This extends the commit 17cea74b also for rectangular textures. They are otherwise lowered to MOV dst temp[0].0000 and deadcode elimitation goes crazy.

Signed-off-by: Pavel Ondračka pavel.ondracka@gmail.com