ice: Correctly initialize queue context values

The ice_alloc_lan_q_ctx function allocates the queue context array for a
given traffic class. This function uses devm_kcalloc which will
zero-allocate the structure. Thus, prior to any queue being setup by
ice_ena_vsi_txq, the q_ctx structure will have a q_handle of 0 and a q_teid
of 0. These are potentially valid values.

Modify the ice_alloc_lan_q_ctx function to initialize every member of the
q_ctx array to have invalid values. Modify ice_dis_vsi_txq to ensure that
it assigns q_teid to an invalid value when it assigns q_handle to the
invalid value as well.

This will allow other code to check whether the queue context is currently
valid before operating on it.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Daniel Machon <daniel.machon@microchip.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Tested-by: Sujai Buvaneswaran <sujai.buvaneswaran@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>