mac80211: drop unused param 'encrypted' from ccmp_special_blocks()

Commit 7ec7c4a9 ("mac80211: port CCMP to cryptoapi's CCM driver")
resulted in the 'encrypted' param of ccmp_special_blocks() to be no
longer used so it can be dropped from the prototype.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>