qtnfmac: Missing platform_device_unregister() on error in qtnf_core_mac_alloc()

Add the missing platform_device_unregister() before return from
qtnf_core_mac_alloc() in the error handling case.

Fixes: 616f5701 ("qtnfmac: assign each wiphy to its own virtual platform device")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Reviewed-by: Sergey Matyukevich <geomatsi@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200730064910.37589-1-wanghai38@huawei.com

drivers/net/wireless/quantenna/qtnfmac/core.c

@@ -446,8 +446,11 @@ static struct qtnf_wmac *qtnf_core_mac_alloc(struct qtnf_bus *bus,
 	}
 
 	wiphy = qtnf_wiphy_allocate(bus, pdev);
-	if (!wiphy)
+	if (!wiphy) {
+		if (pdev)
+			platform_device_unregister(pdev);
 		return ERR_PTR(-ENOMEM);
+	}
 
 	mac = wiphy_priv(wiphy);