fpga: do not access region struct after fpga_region_unregister

A couple drivers were accessing the region struct after it had been
freed.  Save off the pointer to the mgr before the region struct gets
freed.
Signed-off-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fpga/dfl-fme-region.c

@@ -14,6 +14,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/fpga/fpga-mgr.h>
 #include <linux/fpga/fpga-region.h>
 
 #include "dfl-fme-pr.h"
@@ -66,9 +67,10 @@ static int fme_region_probe(struct platform_device *pdev)
 static int fme_region_remove(struct platform_device *pdev)
 {
 	struct fpga_region *region = dev_get_drvdata(&pdev->dev);
+	struct fpga_manager *mgr = region->mgr;
 
 	fpga_region_unregister(region);
-	fpga_mgr_put(region->mgr);
+	fpga_mgr_put(mgr);
 
 	return 0;
 }

drivers/fpga/of-fpga-region.c

@@ -437,9 +437,10 @@ static int of_fpga_region_probe(struct platform_device *pdev)
 static int of_fpga_region_remove(struct platform_device *pdev)
 {
 	struct fpga_region *region = platform_get_drvdata(pdev);
+	struct fpga_manager *mgr = region->mgr;
 
 	fpga_region_unregister(region);
-	fpga_mgr_put(region->mgr);
+	fpga_mgr_put(mgr);
 
 	return 0;
 }