zink: split vertex state pipeline hashing into its own value

zink: split vertex state pipeline hashing into its own value

by creating a separate hash value for vertex state, changes to the vbos and
bindings requires massively less overhead as it doesn't require the rest of
the pipeline state to be rehashed

Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10508>