target/i386: sev: Move local structure definitions into .c file

target/i386: sev: Move local structure definitions into .c file

Neither QSevGuestInfo nor SEVState (not to be confused with SevState) is
used anywhere outside target/i386/sev.c, so they might as well live in
there rather than in a (somewhat) exposed header.

Signed-off-by: David Gibson <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Message-Id: <20200604064219[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>