iwlwifi: mvm: support aggregations on A000 HW

On A000 HW, the SCD rdptr has only 8 bits allocated
for it, thus when checking if a queue is full, or
when checking if the SSN is equal to the TID's
next_reclaimed, A000 HW should trim the SSN.

Fix this by "normalizing" the SSN to wrap around
0xFF when comparing to the next_reclaimed on A000
HW.

Signed-off-by: Liad Kaufman <liad.kaufman@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>