fm10k: reduce the scope of the err variable

Reduce the scope of the local variable err in the fm10k_detach_subtask
function.

This was detected by cppcheck and resolves the following warning
produced by that tool:

[fm10k_pci.c:403]: (style) The scope of the variable 'err' can be reduced.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/fm10k/fm10k_pci.c

 // SPDX-License-Identifier: GPL-2.0
-/* Copyright(c) 2013 - 2018 Intel Corporation. */
+/* Copyright(c) 2013 - 2019 Intel Corporation. */
 
 #include <linux/module.h>
 #include <linux/interrupt.h>
@@ -344,7 +344,6 @@ static void fm10k_detach_subtask(struct fm10k_intfc *interface)
 	struct net_device *netdev = interface->netdev;
 	u32 __iomem *hw_addr;
 	u32 value;
-	int err;
 
 	/* do nothing if netdev is still present or hw_addr is set */
 	if (netif_device_present(netdev) || interface->hw.hw_addr)
@@ -362,6 +361,8 @@ static void fm10k_detach_subtask(struct fm10k_intfc *interface)
 	hw_addr = READ_ONCE(interface->uc_addr);
 	value = readl(hw_addr);
 	if (~value) {
+		int err;
+
 		/* Make sure the reset was initiated because we detached,
 		 * otherwise we might race with a different reset flow.
 		 */