firmware: xilinx: Fix dereferencing freed memory

Fix smatch warning:
drivers/firmware/xilinx/zynqmp.c:1288 zynqmp_firmware_remove()
error: dereferencing freed memory 'feature_data'

Use hash_for_each_safe for safe removal of hash entry.

Fixes: acfdd18591ea ("firmware: xilinx: Use hash-table for api feature check")
Reported-by: kernel test robot <[e-mail]>
Reported-by: Dan Carpenter <[e-mail]>
Signed-off-by: Tejas Patel <[e-mail]>
Signed-off-by: Rajan Vaja <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Michal Simek <[e-mail]>

drivers/firmware/xilinx/zynqmp.c

···
 /*
  * Xilinx Zynq MPSoC Firmware layer
  *
- *  Copyright (C) 2014-2020 Xilinx, Inc.
+ *  Copyright (C) 2014-2021 Xilinx, Inc.
  *
  *  Michal Simek <[e-mail]>
  *  Davorin Mista <[e-mail]>
···
 static int zynqmp_firmware_remove(struct platform_device *pdev)
 {
 	struct pm_api_feature_data *feature_data;
+	struct hlist_node *tmp;
 	int i;
 
 	mfd_remove_devices(&pdev->dev);
 	zynqmp_pm_api_debugfs_exit();
 
-	hash_for_each(pm_api_features_map, i, feature_data, hentry) {
+	hash_for_each_safe(pm_api_features_map, i, tmp, feature_data, hentry) {
 		hash_del(&feature_data->hentry);
 		kfree(feature_data);
 	}