scsi: qedf: Remove set but not used variable 'fr_len'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/scsi/qedf/qedf_fip.c: In function 'qedf_fcoe_send_vlan_req':
drivers/scsi/qedf/qedf_fip.c:22:6: warning:
 variable 'fr_len' set but not used [-Wunused-but-set-variable]

It's never used since introduction and can be removed.
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Manish Rangankar <mrangankar@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qedf/qedf_fip.c

@@ -19,7 +19,6 @@ void qedf_fcoe_send_vlan_req(struct qedf_ctx *qedf)
 {
 	struct sk_buff *skb;
 	char *eth_fr;
-	int fr_len;
 	struct fip_vlan *vlan;
 #define MY_FIP_ALL_FCF_MACS        ((__u8[6]) { 1, 0x10, 0x18, 1, 0, 2 })
 	static u8 my_fcoe_all_fcfs[ETH_ALEN] = MY_FIP_ALL_FCF_MACS;
@@ -29,7 +28,6 @@ void qedf_fcoe_send_vlan_req(struct qedf_ctx *qedf)
 	if (!skb)
 		return;
 
-	fr_len = sizeof(*vlan);
 	eth_fr = (char *)skb->data;
 	vlan = (struct fip_vlan *)eth_fr;