net/mlx5: Avoid blank lines after/before open/close brace

To fix these checkpatch complaints:

CHECK: Blank lines aren't necessary after an open brace '{'
CHECK: Blank lines aren't necessary before a close brace '}'

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>