qcacld-3.0: Return EOPNOTSUPP if fw_mem_dump is not supported
wlan_hdd_cfg80211_get_fw_mem_dump() currently returns ENOTSUPP
if the feature is not supported by firmware. Return EOPNOTSUPP
instead of ENOTSUPP, which looks more appropriate.
Change-Id: I1ca2ebd3fa572ba3caae29ef9f1e396693378fb2
CRs-Fixed: 2088667