pseries: Update MAINTAINERS information

I'm no longer at IBM, and therefore no long actively working on the pseries
(aka sPAPR) qemu machine type.  This patch removes my information in the
MAINTAINERS file.

While we're at it, I've added some extra file patterns for pseries specific
files that weren't included in the existing pattern.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
[agraf: Remove new maintainer addition]
Signed-off-by: NAlexander Graf <agraf@suse.de>

MAINTAINERS

@@ -428,11 +428,14 @@ F: hw/pci/devices/host-prep.[hc]
 F: hw/isa/pc87312.[hc]
 
 sPAPR
-M: David Gibson <david@gibson.dropbear.id.au>
 M: Alexander Graf <agraf@suse.de>
 L: qemu-ppc@nongnu.org
 S: Supported
 F: hw/*/spapr*
+F: include/hw/*/spapr*
+F: hw/*/xics*
+F: include/hw/*/xics*
+F: pc-bios/spapr-rtas/*
 
 virtex_ml507
 M: Edgar E. Iglesias <edgar.iglesias@gmail.com>