st/nine: Allocate more space for ATI1

st/nine: Allocate more space for ATI1

ATIx are "unknown" formats that do not follow block format conventions.
Tests showed that pitch*height bytes are allocated.
apitrace used to depend on this behaviour.
It used to copy more bytes than it has to for the ATI1 block format,
but it didn't crash on Windows.

Increase buffersize for ATI1 to fix this crash.
The same issue was present in WINE but a patch has been sent by me.

Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Axel Davy <axel.davy@ens.fr>