serialio: Preserve Xen DebugOutputPort

xen_preinit() runs early and changes DebugOutputPort.  qemu_preinit() runs
soon after.  inb on DebugOutputPort doesn't work on Xen, so the check
will always fail and DebugOutputPort will be cleared to 0 disabling
output.

Quick exit the function when running on Xen to preserve the modified
DebugOutputPort.

Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
1 file changed
tree: 977673cacb0947fe69d8345fea69f76261486bd6
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  2. COPYING
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  4. Makefile
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  6. docs/
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  8. src/
  9. vgasrc/