iwlwifi: mvm: close the SP if we send fewer frames than expected in SP

When we have holes in the BA window, there might be frames
that have been ACKed between the read and the right
pointers. This means that these frames won't be scheduled
again by the SCD and the firwmare won't see them.
This invalidates the number of frames we tell the firmware
to send. When we detect this case, tell mac80211 to close
the SP and to send an EOSP so that the firmware can be in
sync.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>