iwlwifi: pcie: don't count on the FW to set persistence mode

Apparently the FW can't set the persistence in all flows. Don't count
on the FW setting it in AX210 devices or above either to avoid
potential resets on resume.

Signed-off-by: Haim Dreyfuss <haim.dreyfuss@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20200529092401.5405db448555.Ie3c110932ebbd5b6aca99938a5e0a1e4dfbaa848@changeid