net/mlx5: Assign boolean values to a bool variable

Fix the following coccicheck warnings:

./drivers/net/ethernet/mellanox/mlx5/core/fs_core.c:575:2-14: WARNING:
Assignment of 0/1 to bool variable.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Zhong <abaci-bugfix@linux.alibaba.com>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>