net/mlx5: Switch vport HCA cap helpers to kvzalloc

net/mlx5: Switch vport HCA cap helpers to kvzalloc

mlx5_vport_set_other_func_cap() and mlx5_vport_get_vhca_id() allocate
command buffers that embed the HCA capability union, exceeding 4KiB.
Use kvzalloc/kvfree so the allocation can fall back to vmalloc when
contiguous memory is scarce.

Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20260518071356.345723-5-tariqt@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>