MAINTAINERS: Change status of X86 to Maintained

"Odd Fixes" doesn't reflect the current status of target-i386. We have
people looking after it, now.
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

MAINTAINERS

@@ -173,7 +173,7 @@ X86
 M: Paolo Bonzini <pbonzini@redhat.com>
 M: Richard Henderson <rth@twiddle.net>
 M: Eduardo Habkost <ehabkost@redhat.com>
-S: Odd Fixes
+S: Maintained
 F: target-i386/
 F: hw/i386/