iwlwifi: mvm: support version 7 of the SCAN_REQ_UMAC FW command

Newer firmware versions (such as iwlwifi-8000C-34.ucode) have
introduced an API change in the SCAN_REQ_UMAC command that is not
backwards compatible.  The driver needs to detect and use the new API
format when the firmware reports it, otherwise the scan command will
not work properly, causing a command timeout.

Fix this by adding a TLV that tells the driver that the new API is in
use and use the correct structures for it.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=197591



Fixes: d7a5b3e9 ("iwlwifi: mvm: bump API to 34 for 8000 and up")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>