net/mlx5e: SHAMPO, Fix overflow of hd_per_wq

net/mlx5e: SHAMPO, Fix overflow of hd_per_wq

When having larger RQ sizes and small MTUs sizes, the hd_per_wq variable
can overflow. Like in the following case:

$> ethtool --set-ring eth1 rx 8192
$> ip link set dev eth1 mtu 144
$> ethtool --features eth1 rx-gro-hw on

... yields in dmesg:

mlx5_core 0000:08:00.1: mlx5_cmd_out_err:808:(pid 194797): CREATE_MKEY(0x200) op_mod(0x0) failed, status bad parameter(0x3), syndrome (0x3bf6f), err(-22)

because hd_per_wq is 64K which overflows to 0 and makes the command
fail.

This patch increases the variable size to 32 bit.

Fixes: 99be56171fa9 ("net/mlx5e: SHAMPO, Re-enable HW-GRO")
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>