vdpa/mlx5: fix large VM memory region registration

vdpa/mlx5: fix large VM memory region registration

When VM size is larger than 4G (u32) and memory region is larger than 4G,
the 32-bit GCD function overflowed and returned wrong value
that resulted in memory registration failure.

This patch calls 64-bit GCD function to avoid overflow.

Fixes: cc07a42da250 ("vdpa/mlx5: prepare memory regions")
Cc: stable@dpdk.org
Signed-off-by: Xueming Li <xuemingl@nvidia.com>
Reviewed-by: Matan Azrad <matan@nvidia.com>