mellanox: mlx5: avoid uninitialized variable warning with gcc-12

mellanox: mlx5: avoid uninitialized variable warning with gcc-12

[ Upstream commit 842c3b3ddc5f4d17275edbaa09e23d712bf8b915 ]

gcc-12 started warning about 'tracker' being used uninitialized:

  drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c: In function ‘mlx5_do_bond’:
  drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c:786:28: warning: ‘tracker’ is used uninitialized [-Wuninitialized]
    786 |         struct lag_tracker tracker;
        |                            ^~~~~~~

which seems to be because it doesn't track how the use (and
initialization) is bound by the 'do_bond' flag.

But admittedly that 'do_bond' usage is fairly complicated, and involves
passing it around as an argument to helper functions, so it's somewhat
understandable that gcc doesn't see how that all works.

This function could be rewritten to make the use of that tracker
variable more obviously safe, but for now I'm just adding the forced
initialization of it.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>