common/mlx5: fix build without dlopen option

When setting the CONFIG_RTE_BUILD_SHARED_LIB to y,
and build the mlx5 pmd, there is a building error.
To fix it, add RTE_IBVERBS_LINK_DLOPEN to include
relative codes.

    mlx5_common.o: In function `mlx5_glue_init':
    drivers/common/mlx5/mlx5_common.c:324: undefined reference to `dlclose'

Fixes: 7b4f1e6bd367 ("common/mlx5: introduce common library")
Cc: stable@dpdk.org
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Tested-by: Ali Alnubani <alialnu@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>