iwlwifi: mvm: convert old rate & flags to the new format.

As part of the new rate & flags, convert an old format rate to
the new. This is needed if the driver supports the new format
but the FW supports the old one.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20211017123741.1ea5263dafec.Iadffe7cb26554d4c23c9242eb2ec8326306202a9@changeid


Signed-off-by: Luca Coelho <luciano.coelho@intel.com>