8250_pci: improve code comments and Kconfig help

The recent regression about NetMos 9835 Multi-I/O boards indicates
that comment pointing to the parport_serial driver could be helpful.
Signed-off-by: NStefan Seyfried <seife+kernel@b1-systems.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -4797,6 +4797,12 @@ static struct pci_device_id serial_pci_tbl[] = {
 		PCI_VENDOR_ID_IBM, 0x0299,
 		0, 0, pbn_b0_bt_2_115200 },
 
+	/*
+	 * other NetMos 9835 devices are most likely handled by the
+	 * parport_serial driver, check drivers/parport/parport_serial.c
+	 * before adding them here.
+	 */
+
 	{	PCI_VENDOR_ID_NETMOS, PCI_DEVICE_ID_NETMOS_9901,
 		0xA000, 0x1000,
 		0, 0, pbn_b0_1_115200 },

drivers/tty/serial/8250/Kconfig

@@ -116,6 +116,8 @@ config SERIAL_8250_PCI
 	  This builds standard PCI serial support. You may be able to
 	  disable this feature if you only need legacy serial support.
 	  Saves about 9K.
+	  Note that serial ports on NetMos 9835 Multi-I/O cards are handled
+	  by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
 
 config SERIAL_8250_HP300
 	tristate