pci-assign: Move "Invalid ROM" error message to pci-assign-load-rom.c

In function pci_assign_dev_load_option_rom, For those pci devices don't
have 'rom' file under sysfs or if loading ROM from external file, The
function returns NULL, and won't set the passed 'size' variable.

In these 2 cases, qemu still reports "Invalid ROM" error message, Users
may be confused by it.

Signed-off-by: Lin Ma <lma@suse.com>
Message-Id: <1466010327-22368-1-git-send-email-lma@suse.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/i386/kvm/pci-assign.c

@@ -1891,8 +1891,4 @@ static void assigned_dev_load_option_rom(AssignedDevice *dev)
     pci_assign_dev_load_option_rom(&dev->dev, OBJECT(dev), &size,
                                    dev->host.domain, dev->host.bus,
                                    dev->host.slot, dev->host.function);
-
-    if (!size) {
-        error_report("pci-assign: Invalid ROM.");
-    }
 }

hw/i386/pci-assign-load-rom.c

@@ -40,6 +40,9 @@ void *pci_assign_dev_load_option_rom(PCIDevice *dev, struct Object *owner,
              domain, bus, slot, function);
 
     if (stat(rom_file, &st)) {
+        if (errno != ENOENT) {
+            error_report("pci-assign: Invalid ROM.");
+        }
         return NULL;
     }