bnx2x: Remove set but not used variable 'mfw_vn'

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

drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c: In function 'bnx2x_get_hwinfo':
drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c:11940:10: warning:
 variable 'mfw_vn' set but not used [-Wunused-but-set-variable]

It's never used since introduction.
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Acked-by: NSudarsana Reddy Kalluru <skalluru@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c

@@ -11998,7 +11998,7 @@ static void validate_set_si_mode(struct bnx2x *bp)
 static int bnx2x_get_hwinfo(struct bnx2x *bp)
 {
 	int /*abs*/func = BP_ABS_FUNC(bp);
-	int vn, mfw_vn;
+	int vn;
 	u32 val = 0, val2 = 0;
 	int rc = 0;
 
@@ -12083,12 +12083,10 @@ static int bnx2x_get_hwinfo(struct bnx2x *bp)
 	/*
 	 * Initialize MF configuration
 	 */
-
 	bp->mf_ov = 0;
 	bp->mf_mode = 0;
 	bp->mf_sub_mode = 0;
 	vn = BP_VN(bp);
-	mfw_vn = BP_FW_MB_IDX(bp);
 
 	if (!CHIP_IS_E1(bp) && !BP_NOMCP(bp)) {
 		BNX2X_DEV_INFO("shmem2base 0x%x, size %d, mfcfg offset %d\n",