st/nine: Fix vertex declarations for non-standard (usage/index)

st/nine: Fix vertex declarations for non-standard (usage/index)

Nine code to match vertex declaration to vs inputs was limiting
the number of possible combinations.

Some sm3 games have issues with that, because arbitrary (usage/index)
can be used.

This patch does the following changes to fix the problem:
. Change the numbers given to (usage/index) combinations to uint16
. Do not put limits on the indices when it doesn't make sense
. change the conversion rule (usage/index) -> number to fit all combinations
. Instead of having a table usage_map mapping a (usage/index) number to
an input index, usage_map maps input indices to their (usage/index)

Cc: "10.4" <mesa-stable@lists.freedesktop.org>
Tested-by: Yaroslav Andrusyak <pontostroy@gmail.com>
Acked-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Axel Davy <axel.davy@ens.fr>