[x86] Add guest copy of control registers

o Add control registers for guest.
o Update the guest copy on CRn r/w.
o Update CPU registers accordingly.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
[x86] Auto-creation of guest in DTS.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
[x86] Switch the debug and regular interrupt stack.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
[x86] Fix guest virtual to physical and add other sibling

o Fixes the guest virtual to physical function.
o Add guest physical to host physical address.
o Some documentation around it.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
[x86] Use the new guest virtual to physical family of functions.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
[x86] Reload TSS after VMExit

On vmexit, CPU doesn't reload the host TR back.
It is required because in LM mode its required and
in addition to that we use it for multiple interrupt
stacks.

Signed-off-by: Himanshu Chauhan <hschauhan@nulltrace.org>
Merge x86-next from https://github.com/hschauhan/xvisor-x86_64