Fix KVM_EXIT_IO value address

"kvmRun" *is* a pointer that's the base for to "io.data_offset" so use
that directly. This fixes bogus values being passed to the ioports.

Signed-off-by: Pekka Enberg <penberg@iki.fi>
Fix writes to CMOS data area

Now that KVM_IO_EXIT actually passes non-zero values to the ioports make
sure writes to the CMOS area are emulated. This brings SeaBIOS boot back
to where it was before commit 8973ae0 ("Fix KVM_EXIT_IO value address").

Signed-off-by: Pekka Enberg <penberg@iki.fi>