Replace open-coded test for empty tx ring buffer with equivalent
helper function, uart_circ_empty(). No functional change.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
                uart->port.icount.tx++;
                uart->port.x_char = 0;
                sent = 1;
-       } else if (xmit->tail != xmit->head) {  /* TODO: uart_circ_empty */
+       } else if (!uart_circ_empty(xmit)) {
                ch = xmit->buf[xmit->tail];
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                uart->port.icount.tx++;