net/mlx5e: xsk: Account for XSK RQ UMRs when calculating ICOSQ size

ICOSQ is used to post UMR WQEs for both regular RQ and XSK RQ. However,
space in ICOSQ is reserved only for the regular RQ, which may cause
ICOSQ overflows when using XSK (the most risk is on activating
channels).

This commit fixes the issue by reserving space for XSK UMR WQEs as well.
As XSK may be enabled without restarting the channel and recreating the
ICOSQ, this space is reserved unconditionally.

Fixes: db05815b ("net/mlx5e: Add XSK zero-copy support")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>