ice: add useful statistics

Display and count some useful hot-path statistics. The usefulness is as
follows:

- tx_restart: use to determine if the transmit ring size is too small or
  if the transmit interrupt rate is too low.
- rx_gro_dropped: use to count drops from GRO layer, which previously were
  completely uncounted when occurring.
- tx_busy: use to determine when the driver is miscounting number of
  descriptors needed for an skb.
- tx_timeout: as our other drivers, count the number of times we've reset
  due to timeout because the kernel only prints a warning once per netdev.

Several of these were already counted but not displayed.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice.h

@@ -256,6 +256,7 @@ struct ice_vsi {
 	u32 tx_busy;
 	u32 rx_buf_failed;
 	u32 rx_page_failed;
+	u32 rx_gro_dropped;
 	u16 num_q_vectors;
 	u16 base_vector;		/* IRQ base for OS reserved vectors */
 	enum ice_vsi_type type;