freedreno/ir3: Extend geometry lowering pass to handle tessellation

freedreno/ir3: Extend geometry lowering pass to handle tessellation

VS and TCS pass varyings the same way as VS and GS does. TCS then
writes entire patch to a system memory BO and TES eventually reads
back from the BO once the TE starts generating vertices.  TES outputs
vertices the same way as VS and GS, except when there's a GS as well,
in which case TES passes varyings to GS same way the VS would.

In addition, the TCS needs a little bit of control flow massaging so
that it only runs for valid invocations needs a couple of unknown
instructions to synchronize with the TE.

Signed-off-by: Kristian H. Kristensen <hoegsberg@google.com>
Acked-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Rob Clark <robdclark@gmail.com>