KVM: Retire as maintainer

After six and a half years of writing and maintaining KVM, it is time to
move to new things.  Update my MAINTAINERS entry to reflect that.

Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/CREDITS b/CREDITS
index d8fe12a..2346b09 100644
--- a/CREDITS
+++ b/CREDITS
@@ -1823,6 +1823,11 @@
 S: D-64295
 S: Germany
 
+N: Avi Kivity
+E: avi.kivity@gmail.com
+D: Kernel-based Virtual Machine (KVM)
+S: Ra'annana, Israel
+
 N: Andi Kleen
 E: andi@firstfloor.org
 U: http://www.halobates.de