wifi: iwlwifi: debug: fix crash in __iwl_err()

wifi: iwlwifi: debug: fix crash in __iwl_err()

In __iwl_err(), if we rate-limit the message away, then
vaf.va is still NULL-initialized by the time we get to
the tracing code, which then crashes. When it doesn't
get rate-limited out, it's still wrong to reuse the old
args2 that was already printed, which is why we bother
making a copy in the first place.

Assign vaf.va properly to fix this.

Fixes: e5f1cc98cc1b ("iwlwifi: allow rate-limited error messages")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230413102635.e27134c6bcd4.Ib3894cd2ba7a5ad5e75912a7634f146ceaa569e2@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>