usb: gadget: udc: bcm63xx: Convert to use list_count_nodes()

The list API provides the list_count_nodes() to help with counting
existing nodes in the list. Utilise it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221130134838.23805-3-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/bcm63xx_udc.c

@@ -2172,7 +2172,6 @@ static int bcm63xx_iudma_dbg_show(struct seq_file *s, void *p)
 
 	for (ch_idx = 0; ch_idx < BCM63XX_NUM_IUDMA; ch_idx++) {
 		struct iudma_ch *iudma = &udc->iudma[ch_idx];
-		struct list_head *pos;
 
 		seq_printf(s, "IUDMA channel %d -- ", ch_idx);
 		switch (iudma_defaults[ch_idx].ep_type) {
@@ -2205,14 +2204,10 @@ static int bcm63xx_iudma_dbg_show(struct seq_file *s, void *p)
 		seq_printf(s, "  desc: %d/%d used", iudma->n_bds_used,
 			   iudma->n_bds);
 
-		if (iudma->bep) {
-			i = 0;
-			list_for_each(pos, &iudma->bep->queue)
-				i++;
-			seq_printf(s, "; %d queued\n", i);
-		} else {
+		if (iudma->bep)
+			seq_printf(s, "; %zu queued\n", list_count_nodes(&iudma->bep->queue));
+		else
 			seq_printf(s, "\n");
-		}
 
 		for (i = 0; i < iudma->n_bds; i++) {
 			struct bcm_enet_desc *d = &iudma->bd_ring[i];