MAINTAINERS: Include X86CPU in CPU maintenance area

Document that the x86 CPU refactorings are going through the qom-cpu
tree. This does not contradict the established practice that patches
adding KVM features to the x86 CPU go through the KVM maintainers,
it merely takes it out of target-i386 TCG's Odd Fixes status.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Cc: Marcello Tosatti <mtosatti@redhat.com>

MAINTAINERS

@@ -599,6 +599,7 @@ M: Andreas Färber <afaerber@suse.de>
 S: Supported
 F: qom/cpu.c
 F: include/qemu/cpu.h
+F: target-i386/cpu.c
 
 Device Tree
 M: Peter Crosthwaite <peter.crosthwaite@petalogix.com>