net/mlx5e: XDP, Fix shifted flag index in RQ bitmap

Values in enum mlx5e_rq_flag are used as bit indixes.
Intention was to use them with no BIT(i) wrapping.

No functional bug fix here, as the same (shifted)flag bit
is used for all set, test, and clear operations.

Fixes: 121e8927 ("net/mlx5e: Refactor RQ XDP_TX indication")
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Reviewed-by: Shay Agroskin <shayag@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>