turnip: Gather information for transform feedback

turnip: Gather information for transform feedback

- Add one member to the existed ir3_stream_output so that we could
assign location information from nir_xfb_info, rather than defining
new struct.

- Redefine maximum of so buffers, streams and outputs, which will be
used for turnip.

- Also enable caps for transform feedback for spirv_to_nir.

v2. Remove redefined maximums and use IR3_MAX_SO_* and add
IR3_MAX_SO_STREAMS.

v3. Remove the newly added location field so that we could keep aligned
with 32 bytes. Instead we create an array mapping between the location
and consecutive index, which is GL driver is doing.

Signed-off-by: Hyunjun Ko <zzoon@igalia.com>
Reviewed-by: Jonathan Marek <jonathan@marek.ca>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3942>