KVM: powerpc: Change maintainer

Progress on KVM for Embedded PowerPC has stalled, but for Book3S there's quite
a lot of work to do and going on.

So in agreement with Hollis and Avi, we should switch maintainers for PowerPC.

Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Hollis Blanchard <hollis@penguinppc.org>
Signed-off-by: Avi Kivity <avi@redhat.com>

MAINTAINERS

@@ -3167,7 +3167,7 @@ F:	arch/x86/include/asm/svm.h
 F:	arch/x86/kvm/svm.c
 
 KERNEL VIRTUAL MACHINE (KVM) FOR POWERPC
-M:	Hollis Blanchard <hollisb@us.ibm.com>
+M:	Alexander Graf <agraf@suse.de>
 L:	kvm-ppc@vger.kernel.org
 W:	http://kvm.qumranet.com
 S:	Supported