mlx5: fix build with debugging enabled

mlx5: fix build with debugging enabled

The following error occurs when CONFIG_RTE_LIBRTE_MLX5_DEBUG=y:

 drivers/net/mlx5/mlx5.c:381:4: error: ISO C forbids braced-groups within expressions

RTE_MIN() uses the non-standard ({ ... }) syntax to declare variables within
parentheses, which is rejected by -pedantic.

Since the RSS_INDIRECTION_TABLE_SIZE check is meant to go away as soon as
DPDK supports larger/variable indirection tables, put it in a separate
condition.

Fixes: 634efbc2c8c0 ("mlx5: support RETA query and update")

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>