net: rfkill: Correct return value in invalid parameter case

rfkill_set_hw_state_reason() does not return current combined
block state when its parameter @reason is invalid, that is
wrong according to its comments, fix it by correcting the
value returned.

Also reformat the WARN while at it.

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://patch.msgid.link/1718287476-28227-1-git-send-email-quic_zijuhu@quicinc.com
[edit/reformat commit message, remove unneeded variable]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>