qcacld-3.0: Free sta_self_wmi_rsp if WMA_DELETE_STA_REQ is not queued

In wma_self_peer_remove, sta_self_wmi_rsp is allocated and sent as
params to wma_fill_hold_req for WMA_DELETE_STA_REQ. However, if
wma_fill_hold_req fails and returns NULL, the memory allocated for
sta_self_wmi_rsp is not freed leading to memory leak.

Free sta_self_wmi_rsp in the error handling case for wma_fill_hold_req
in wma_self_peer_remove.

Change-Id: I8df840b39284e00a8c8be114c0fec13c3c199fc6
CRs-Fixed: 2334580