wifi: ath12k: fix potential memory leak in ath12k_wow_arp_ns_offload()

wifi: ath12k: fix potential memory leak in ath12k_wow_arp_ns_offload()

When the call to ath12k_wmi_arp_ns_offload() fails, the temporary memory
allocation for offload is not freed before returning. Fix that by
freeing offload in the error path.

Fixes: 1666108c74c4 ("wifi: ath12k: support ARP and NS offload")
Signed-off-by: Abdun Nihaal <nihaal@cse.iitm.ac.in>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Link: https://patch.msgid.link/20251028170457.134608-1-nihaal@cse.iitm.ac.in
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>