vfio/mlx5: Fix a typo in mlx5vf_cmd_load_vhca_state()

Fix a typo in mlx5vf_cmd_load_vhca_state() to use the 'load' memory
layout.

As in/out sizes are equal for save and load commands there wasn't any
functional issue.

Fixes: f1d98f34

 ("vfio/mlx5: Expose migration commands over mlx5 device")
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20221106174630.25909-3-yishaih@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>