i965: Fix off-by-one in query object result gathering.

i965: Fix off-by-one in query object result gathering.

If we've written N pairs of values to the buffer, then last_index = N,
but the values are 0 .. N-1.  Thus, we need to use <, not <=.

This worked anyway because we fill the buffer with zeroes, so we just
added an extra (0 - 0) to our results.

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