X86 QBE: Make some X86 routines virtual

Add virtual in one place, and move some code into a virtual routine.
This allows subclassing and overriding for my purposes.

Change-Id: Ie415df943b17b56ad1f057513b2df2a31801a72f
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>
2 files changed