i965/fs: Make the FS binding table as small as possible.

i965/fs: Make the FS binding table as small as possible.

Computing the minimum size was easy, and done at compile-time for no
extra overhead here.  Making the binding table smaller wastes less batch
space.

Adding the CACHE_NEW_WM_PROG dirty bit isn't strictly necessary, since
other atoms depend on it and flag BRW_NEW_SURFACES.  However, it's best
to add it for clarity and safety.  It shouldn't add any new overhead.

v2: Use binding_table_size, rather than max_surface_index.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>