i965: Move binding table update packets to binding table setup time.

i965: Move binding table update packets to binding table setup time.

This keeps us from needing to reemit all the other stage state just
because a surface changed.

Improves unoptimized glamor x11perf -f8text by 1.10201% +/- 0.489869%
(n=296). [v1]

v2:
 - Drop binding table packets from Gen8 unit state as well.
 - Pass _3DSTATE_BINDING_TABLE_POINTERS_XS to brw_upload_binding_table,
   cutting even more code.
v3: Don't forget to drop them from 3DSTATE_GS (botched refactor in v2).

Signed-off-by: Eric Anholt <eric@anholt.net> [v1]
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org> [v1]
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> [v2, v3]
Reviewed-by: Eric Anholt <eric@anholt.net> [v3]