i965: Fix INTEL_DEBUG=bat

i965: Fix INTEL_DEBUG=bat

Use hash_table_u64 instead of hash_table directly, since the former
will also handle the special keys (deleted and freed) and allow use
the whole u64 space.

Fixes crash in INTEL_DEBUG=bat when using a key with value 0 -- the
current value for a freed key.

Fixes: b38dab101ca "util/hash_table: Assert that keys are not reserved pointers"
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>