net/mlx5e: Fix macsec coverity issue at rx sa update

The cited commit at update rx sa operation passes object attributes
to MACsec object create function without initializing/setting all
attributes fields leaving some of them with garbage values, therefore
violating the implicit assumption at create object function, which
assumes that all input object attributes fields are set.

Fix by initializing the object attributes struct to zero, thus leaving
unset fields with the legal zero value.

Fixes: aae3454e

 ("net/mlx5e: Add MACsec offload Rx command support")
Signed-off-by: Raed Salem <raeds@nvidia.com>
Reviewed-by: Lior Nahmanson <liorna@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Link: https://lore.kernel.org/r/20221026135153.154807-13-saeed@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>