freedreno/ir3: move inputs/outputs to shader

freedreno/ir3: move inputs/outputs to shader

These belong in the shader, rather than the block.  Mostly a lot of
churn and nothing too interesting.  But splitting this out from the
rest of ir3_block reshuffling to cut down the noise in the later
patch.

Signed-off-by: Rob Clark <robclark@freedesktop.org>