MAINTAINERS: Add myself as scheduler topology reviewer

I've messed around the NUMA/debug bits of the scheduler toplogy in my
time at Arm, and even though I've changed ships I still intend to at the
very least review those bits.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220406141315.732473-2-vschneid@redhat.com

Author: valschneider

MAINTAINERS

@@ -17508,6 +17508,7 @@ R:	Steven Rostedt <rostedt@goodmis.org> (SCHED_FIFO/SCHED_RR)
 R:	Ben Segall <bsegall@google.com> (CONFIG_CFS_BANDWIDTH)
 R:	Mel Gorman <mgorman@suse.de> (CONFIG_NUMA_BALANCING)
 R:	Daniel Bristot de Oliveira <bristot@redhat.com> (SCHED_DEADLINE)
+R:	Valentin Schneider <vschneid@redhat.com> (TOPOLOGY)
 L:	linux-kernel@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core