RDMA/mlx4: Avoid false error about access to uninitialized gids array

Smatch generates the following false error report:
drivers/infiniband/hw/mlx4/main.c:393 mlx4_ib_del_gid() error: uninitialized symbol 'gids'.

Traditionally, we are not changing kernel code and asking people to fix
the tools. However in this case, the fix can be done by simply rearranging
the code to be more clear.

Fixes: e26be1bf ("IB/mlx4: Implement ib_device callbacks")
Link: https://patch.msgid.link/6a3a1577463da16962463fcf62883a87506e9b62.1733233426.git.leonro@nvidia.com


Signed-off-by: Leon Romanovsky <leonro@nvidia.com>