ice: Updates to Tx scheduler code

1) The maximum device nodes is a global value and shared by the whole
   device. Add element AQ command would fail if there is no space to
   add new nodes so the check for max nodes isn't required. So remove
   ice_sched_get_num_nodes_per_layer and ice_sched_val_max_nodes.

2) In ice_sched_add_elems, set default node's CIR/EIR bandwidth weight.

3) Fix default scheduler topology buffer size as the firmware expects
   a 4KB buffer at all times, and will error out if one of any other
   size is provided.

4) In the latest spec, max children per node per layer is replaced by
   max sibling group size. Now it provides the max children of the below
   layer node, not the current layer node.

5) Fix some newline/whitespace issues for consistency.

Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>