igb: Fix a memory leak in igb_probe

In error handling code of igb_probe, the memory adapter->shadow_vfta
allocated by kcalloc in igb_sw_init is not freed. So when register_netdev
or igb_init_i2c is failed, a memory leak will occur.
This patch adds kfree to fix it.

Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/igb_main.c

@@ -2649,6 +2649,7 @@ err_eeprom:
 	if (hw->flash_address)
 		iounmap(hw->flash_address);
 err_sw_init:
+	kfree(adapter->shadow_vfta);
 	igb_clear_interrupt_scheme(adapter);
 	pci_iounmap(pdev, hw->hw_addr);
 err_ioremap: