i386/pc: '-drive if=floppy' should imply a board-default FDC

Even if board code decides not to request the creation of the FDC (keyed
off board-level factors, to be determined later), we should create the FDC
nevertheless if the user passes '-drive if=floppy' on the command line.

Otherwise '-drive if=floppy' would break without explicit '-device
isa-fdc' on such boards.

Cc: Markus Armbruster <armbru@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: John Snow <jsnow@redhat.com>
Cc: "Gabriel L. Somlo" <gsomlo@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-block@nongnu.org
Signed-off-by: NLaszlo Ersek <lersek@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>

hw/i386/pc.c

@@ -1490,6 +1490,7 @@ void pc_basic_device_init(ISABus *isa_bus, qemu_irq *gsi,
 
     for(i = 0; i < MAX_FD; i++) {
         fd[i] = drive_get(IF_FLOPPY, 0, i);
+        create_fdctrl |= !!fd[i];
     }
     *floppy = create_fdctrl ? fdctrl_init_isa(isa_bus, fd) : NULL;
 }