i965: Un-hardcode WM binding table from update_texture_surface.

i965: Un-hardcode WM binding table from update_texture_surface.

Currently, we mirror the VS and WM binding tables' texture entries.
That may not continue to be true, so in preparation, pass in the binding
table and surface index as arguments.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>