tty: synclink_gt: use true,false for bool variable

Fixes coccicheck warning:

drivers/tty/synclink_gt.c:2101:3-19: WARNING: Assignment of 0/1 to bool variable

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Link: https://lore.kernel.org/r/1578881777-65475-2-git-send-email-zhengbin13@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/synclink_gt.c

@@ -2098,7 +2098,7 @@ static void isr_rxdata(struct slgt_info *info)
 		if (desc_complete(info->rbufs[i])) {
 			/* all buffers full */
 			rx_stop(info);
-			info->rx_restart = 1;
+			info->rx_restart = true;
 			continue;
 		}
 		info->rbufs[i].buf[count++] = (unsigned char)reg;