serial: 8250_pci: Remove empty stub pci_quatech_exit()

The ->exit() callback is checked for presence anyway,
no need to have an empty stub.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211026133452.61657-2-andriy.shevchenko@linux.intel.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_pci.c

@@ -1298,10 +1298,6 @@ static int pci_quatech_setup(struct serial_private *priv,
 	return pci_default_setup(priv, board, port, idx);
 }
 
-static void pci_quatech_exit(struct pci_dev *dev)
-{
-}
-
 static int pci_default_setup(struct serial_private *priv,
 		  const struct pciserial_board *board,
 		  struct uart_8250_port *port, int idx)
@@ -2176,7 +2172,6 @@ static struct pci_serial_quirk pci_serial_quirks[] = {
 		.subdevice	= PCI_ANY_ID,
 		.init		= pci_quatech_init,
 		.setup		= pci_quatech_setup,
-		.exit		= pci_quatech_exit,
 	},
 	/*
 	 * Panacom