ixgbevf: fix possible use of uninitialized variable

This patch resolves the following warning:

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c: In function ‘ixgbevf_probe’:
drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c:1742:290: warning: ‘err’ may be used uninitialized in this function [-Wuninitialized]
drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c:1717:6: note: ‘err’ was declared here

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

@@ -1724,7 +1724,8 @@ void ixgbevf_reset(struct ixgbevf_adapter *adapter)
 static int ixgbevf_acquire_msix_vectors(struct ixgbevf_adapter *adapter,
 					int vectors)
 {
-	int err, vector_threshold;
+	int err = 0;
+	int vector_threshold;
 
 	/* We'll want at least 2 (vector_threshold):
 	 * 1) TxQ[0] + RxQ[0] handler