i965: Use the blitter in intel_bufferobj_subdata for busy BOs on Gen6+.

Previously we only did this pre-Gen6, and used pwrite on Gen6+.
In one workload, this cuts significant amount of overhead.

v2: Simplify the function based on Eric's suggestions.

Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
1 file changed