wifi: iwlwifi: fw: pnvm: fix uefi reduced TX power loading

wifi: iwlwifi: fw: pnvm: fix uefi reduced TX power loading

There are a number of issues here:
 * if trans->reduce_power_loaded is already true, we call
   iwl_trans_set_reduce_power() with an uninitialized len
   value
 * in this case we also clobber a previous load/setting
 * if iwl_uefi_get_reduced_power() returns an ERR_PTR() we
   try to kfree() it

Move the iwl_trans_set_reduce_power() call into the success
case only to fix these issues.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230314194113.aa2cf2281f5d.I33b4ab3427f1921c184c52fecd0f46781a89dc8a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>