q800: fix I/O memory map

q800: fix I/O memory map

Linux kernel 5.4 will introduce a new memory map for SWIM device.
(aee6bff1c325 ("m68k: mac: Revisit floppy disc controller base addresses"))

Until this release all MMIO are mapped between 0x50f00000 and 0x50f40000,
but it appears that for real hardware 0x50f00000 is not the base address:
the MMIO region spans 0x50000000 through 0x60000000, and 0x50040000 through
0x54000000 is repeated images of 0x50000000 to 0x50040000.

Fixed: 04e7ca8d0f ("hw/m68k: define Macintosh Quadra 800")
Signed-off-by: Laurent Vivier <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Message-Id: <20191104101513[email protected]>
Signed-off-by: Laurent Vivier <[email protected]>