net/mlx5e: Use unsigned for mlx5e_get_max_num_channels

The max number of channels is always an unsigned int, use the correct
type to fix compilation errors done with strict type checking, e.g.:

error: call to ‘__compiletime_assert_1110’ declared with attribute
  error: min(mlx5e_get_devlink_param_num_doorbells(mdev),
  mlx5e_get_max_num_channels(mdev)) signedness error

Fixes: 74a8dad ("net/mlx5e: Preparations for supporting larger number of channels")
Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jacob Keller <Jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260218072904.1764634-7-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Cosmin Ratiu

drivers/net/ethernet/mellanox/mlx5/core/en.h

@@ -180,7 +180,8 @@ static inline u16 mlx5_min_rx_wqes(int wq_type, u32 wq_size)
 }
 
 /* Use this function to get max num channels (rxqs/txqs) only to create netdev */
-static inline int mlx5e_get_max_num_channels(struct mlx5_core_dev *mdev)
+static inline unsigned int
+mlx5e_get_max_num_channels(struct mlx5_core_dev *mdev)
 {
 	return is_kdump_kernel() ?
 		MLX5E_MIN_NUM_CHANNELS :