net/mlx5e: Fix incompatible casting

Device supports setting of a single fec mode at a time, enforce this
by bitmap_weight == 1. Input from fec command is in u32, avoid cast to
unsigned long and use bitmap_from_arr32 to populate bitmap safely.

Fixes: 4bd9d507 ("net/mlx5e: Enforce setting of a single FEC mode")
Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c

@@ -1624,12 +1624,13 @@ static int mlx5e_set_fecparam(struct net_device *netdev,
 {
 	struct mlx5e_priv *priv = netdev_priv(netdev);
 	struct mlx5_core_dev *mdev = priv->mdev;
+	unsigned long fec_bitmap;
 	u16 fec_policy = 0;
 	int mode;
 	int err;
 
-	if (bitmap_weight((unsigned long *)&fecparam->fec,
-			  ETHTOOL_FEC_LLRS_BIT + 1) > 1)
+	bitmap_from_arr32(&fec_bitmap, &fecparam->fec, sizeof(fecparam->fec) * BITS_PER_BYTE);
+	if (bitmap_weight(&fec_bitmap, ETHTOOL_FEC_LLRS_BIT + 1) > 1)
 		return -EOPNOTSUPP;
 
 	for (mode = 0; mode < ARRAY_SIZE(pplm_fec_2_ethtool); mode++) {