CC312: Remove stray 'buffAttr' argument from ProcessAesCcmDrv call

The code containing the bug is only compiled if `AES_NO_TUNNEL` is defined.

Signed-off-by: Abbas Bracken Ziad <abbas.brackenziad@arm.com>
Change-Id: I028236adbf217ff7b2f643b08dff9c64c33ed215