vga: fix bochs alignment issue

The bochs dispi interface traditionally uses port 0x1ce as 16bit index
register and port 0x1cf as 16bit data register.  The later is unaligned,
and probably for that reason the the data register was moved to 0x1d0
for non-x86 archs.

This patch makes the data register available at 0x1d0 on x86 too.  The
old x86 location is kept for compatibility reasons, so both 0x1cf and
0x1d0 can be used as data register on x86.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

docs/specs/standard-vga.txt

@@ -36,7 +36,8 @@ IO ports used
 
 03c0 - 03df : standard vga ports
 01ce        : bochs vbe interface index port
-01cf        : bochs vbe interface data port
+01cf        : bochs vbe interface data port (x86 only)
+01d0        : bochs vbe interface data port
 
 
 Memory regions used

hw/vga.c

@@ -2321,9 +2321,8 @@ static const MemoryRegionPortio vbe_portio_list[] = {
     { 0, 1, 2, .read = vbe_ioport_read_index, .write = vbe_ioport_write_index },
 # ifdef TARGET_I386
     { 1, 1, 2, .read = vbe_ioport_read_data, .write = vbe_ioport_write_data },
-# else
-    { 2, 1, 2, .read = vbe_ioport_read_data, .write = vbe_ioport_write_data },
 # endif
+    { 2, 1, 2, .read = vbe_ioport_read_data, .write = vbe_ioport_write_data },
     PORTIO_END_OF_LIST(),
 };