iwlwifi: mvm: prepare infrastructure for more TLV flags

We use the TLV flags as a handshake between the firmware
and the driver. These flags allow the firmware to advertise
its capabilities and API version.
Since we are running short of bits, we add a new
infrastructure which is more scalable, yet backward
compatible.

We make now the difference between API changes and the
capabilities. Both can have an index which allows to scale
at will.

Signed-off-by: Eran Harary <eran.harary@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>