iwlwifi: use longer queues for 256-BA

When we have 256 block-ack support, we may need to be very fast
to provide a lot of frames to the hardware to transmit, but that
cannot be guaranteed. Use a longer queue size to have more time,
and the next possible queue size is 1024 since it must be a power
of two.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20200425130140.851866c7e4c4.I13fa678929431f1694fd202c1da40aa476ab70fe@changeid