net/mlx5: {DR,HWS}, Use the cached vhca_id for this device

The mlx5 driver caches many capabilities to be used by mlx5 layers.

In SW and HW steering we can use the cached vhca_id instead of invoking
FW commands.

Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250829223722.900629-8-saeed@kernel.org


Signed-off-by: Paolo Abeni <pabeni@redhat.com>