iwlwifi: acpi: fill in SAR tables with defaults

If the tables we get in the iwl_sar_set_profile() is smaller than the
revision we support, we need to fill the values with 0.  Make sure
that's the case.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210819183728.7fb9716db7ba.I75541846e0720f80695186ba39398133c8758280@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>