freedreno/ir3: bit of shader API refactoring

freedreno/ir3: bit of shader API refactoring

Since for transform-feedback, we'll need more than just the TGSI
tokens from the state object, just pass the entire state object to
ir3_shader_create().  This also cleans things up a bit for some
day in the future when we could take shader either as TGSI or
directly NIR (for ex, glsl2nir or spirv2nir paths).  In the same
spirit, drop extra args from ir3_compile_shader_nir() (since it
can anyways get what it needs from the ir3_shader_variant).

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