target/i386: sev: Unify SEVState and SevGuestState

target/i386: sev: Unify SEVState and SevGuestState

SEVState is contained with SevGuestState.  We've now fixed redundancies
and name conflicts, so there's no real point to the nested structure.  Just
move all the fields of SEVState into SevGuestState.

This eliminates the SEVState structure, which as a bonus removes the
confusion with the SevState enum.

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]>