iwlwifi: mvm: improve latency when there is a reorder timeout

When there is a reorder timeout, we may get to a situation
where we have the timeout latency for all the next 64 frames.
This happens since NSSN is behind for a while, and the driver
won't release the frames, since it is not allowed by NSSN.
As a result the frame is stored in the reorder buffer although
there is no hole, and released 100 ms later.
Add a direct comparison to the reorder buffer head, and release
immediately if possible.

For example:
Frame 0 is missed. We receive frame 1, and store it in the buffer.
After 100 ms, frame 1 is released and reorder buffer head is 2.
We then receive frame 2, with NSSN 0, and store it instead of
releasing it.

Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>