ns16550: make PCI device hiding uniform

The difference between pci_hide_device() and pci_ro_device() is that
the former only prevents a device from getting assigned to a guest,
while the latter additionally arranges for Dom0 write attempts to the
device's config space to be ignored/discarded. Whether we want one or
the other certainly doesn't depend on whether the device is in our set
of known devices. All that matters is whether we use a PCI device: Call
pci_ro_device() in any such case.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Julien Grall <julien.grall@arm.com>

xen/drivers/char/ns16550.c

@@ -763,23 +763,16 @@ static void __init ns16550_init_postirq(struct serial_port *port)
 #ifdef CONFIG_HAS_PCI
     if ( uart->bar || uart->ps_bdf_enable )
     {
-        if ( !uart->param )
-            pci_hide_device(0, uart->ps_bdf[0], PCI_DEVFN(uart->ps_bdf[1],
-                            uart->ps_bdf[2]));
-        else
-        {
-            if ( uart->param->mmio &&
-                 rangeset_add_range(mmio_ro_ranges,
-                                    uart->io_base,
-                                    uart->io_base + uart->io_size - 1) )
-                printk(XENLOG_INFO "Error while adding MMIO range of device to mmio_ro_ranges\n");
+        if ( uart->param && uart->param->mmio &&
+             rangeset_add_range(mmio_ro_ranges, uart->io_base,
+                                uart->io_base + uart->io_size - 1) )
+            printk(XENLOG_INFO "Error while adding MMIO range of device to mmio_ro_ranges\n");
 
-            if ( pci_ro_device(0, uart->ps_bdf[0],
-                               PCI_DEVFN(uart->ps_bdf[1], uart->ps_bdf[2])) )
-                printk(XENLOG_INFO "Could not mark config space of %02x:%02x.%u read-only.\n",
-                                    uart->ps_bdf[0], uart->ps_bdf[1],
-                                    uart->ps_bdf[2]);
-        }
+        if ( pci_ro_device(0, uart->ps_bdf[0],
+                           PCI_DEVFN(uart->ps_bdf[1], uart->ps_bdf[2])) )
+            printk(XENLOG_INFO "Could not mark config space of %02x:%02x.%u read-only.\n",
+                   uart->ps_bdf[0], uart->ps_bdf[1],
+                   uart->ps_bdf[2]);
 
         if ( uart->msi )
         {