hw/usb: Extract VT82C686 UHCI PCI function into a new unit

Extract the VT82C686 PCI UHCI function into a new unit so
it is only build when the VT82C686 south bridge is selected.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210309190802.830969-4-f4bug@amsat.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 5ca3c9f..b6ab3d2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1180,6 +1180,7 @@
 F: hw/mips/fuloong2e.c
 F: hw/isa/vt82c686.c
 F: hw/pci-host/bonito.c
+F: hw/usb/vt82c686-uhci-pci.c
 F: include/hw/isa/vt82c686.h
 
 Loongson-3 virtual platforms