vga: fix bochs alignment issue

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: Gerd Hoffmann <kraxel@redhat.com>