iris: Allow max dynamic pool size of 2GB for gen12

Reworks:
 * Adjust comment to list the state packets that curro found to be
   affected.

Fixes: 8125d796 ("intel/dev: Add preliminary device info for Tigerlake")
Cc: 19.3 <mesa-stable@lists.freedesktop.org>
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Acked-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
(cherry picked from commit e277009d)