ice: Minor refactor in queue management

Remove q_left_tx and q_left_rx from the PF struct as these can be
obtained by calling ice_get_avail_txq_count and ice_get_avail_rxq_count
respectively.

The function ice_determine_q_usage is only setting num_lan_tx and
num_lan_rx in the PF structure, and these are later assigned to
vsi->alloc_txq and vsi->alloc_rxq respectively. This is an unnecessary
indirection, so remove ice_determine_q_usage and just assign values
for vsi->alloc_txq and vsi->alloc_rxq in ice_vsi_set_num_qs and use
these to set num_lan_tx and num_lan_rx respectively.

Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>