wifi: iwlwifi: fw: move memset before early return

wifi: iwlwifi: fw: move memset before early return

Clang static analysis reports this representative issue
dbg.c:1455:6: warning: Branch condition evaluates to
a garbage value
  if (!rxf_data.size)
       ^~~~~~~~~~~~~~

This check depends on iwl_ini_get_rxf_data() to clear
rxf_data but the function can return early without
doing the clear.  So move the memset before the early
return.

Fixes: cc9b6012d34b ("iwlwifi: yoyo: use hweight_long instead of bit manipulating")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230414130637.872a7175f1ff.I33802a77a91998276992b088fbe25f61c87c33ac@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>