usb: xhci: Fix bool initialization in xhci_bulk_tx

Bool initializations should use true and false.

This issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Marek Vasut <marex@denx.de>

drivers/usb/host/xhci-ring.c

@@ -557,7 +557,7 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
 {
 	int num_trbs = 0;
 	struct xhci_generic_trb *start_trb;
-	bool first_trb = 0;
+	bool first_trb = false;
 	int start_cycle;
 	u32 field = 0;
 	u32 length_field = 0;