MAINTAINERS: make block I/O path Stefan Hajnoczi's responsibility

The block I/O path includes the asynchronous I/O machinery and
read/write/flush/discard processing.  It somewhat arbitrarily also
includes block migration, which I've found myself reviewing patches for
over the years.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

MAINTAINERS

@@ -774,12 +774,9 @@ Block
 M: Kevin Wolf <kwolf@redhat.com>
 M: Stefan Hajnoczi <stefanha@redhat.com>
 S: Supported
-F: async.c
-F: aio-*.c
 F: block*
 F: block/
 F: hw/block/
-F: migration/block*
 F: qemu-img*
 F: qemu-io*
 F: tests/image-fuzzer/
@@ -787,6 +784,16 @@ F: tests/qemu-iotests/
 T: git git://repo.or.cz/qemu/kevin.git block
 T: git git://github.com/stefanha/qemu.git block
 
+Block I/O path
+M: Stefan Hajnoczi <stefanha@redhat.com>
+L: qemu-block@nongnu.org
+S: Supported
+F: async.c
+F: aio-*.c
+F: block/io.c
+F: migration/block*
+T: git git://github.com/stefanha/qemu.git block
+
 Block Jobs
 M: Jeff Cody <jcody@redhat.com>
 L: qemu-block@nongnu.org