MAINTAINERS: add Andrew and Baoquan as kexec maintainers

Add Andrew as kexec/kdump maintainer because he has been helping review
and merge ready kexec/kdump patches.

And I would like to nominate myself as kexec maintainer because I always
try to review generic kexec codes.

Link: https://lkml.kernel.org/r/20250328104402.16826-1-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Simon Horman <horms@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Baoquan He

MAINTAINERS

@@ -12810,6 +12810,7 @@ F:	lib/Kconfig.kcsan
 F:	scripts/Makefile.kcsan
 
 KDUMP
+M:	Andrew Morton <akpm@linux-foundation.org>
 M:	Baoquan He <bhe@redhat.com>
 R:	Vivek Goyal <vgoyal@redhat.com>
 R:	Dave Young <dyoung@redhat.com>
@@ -13111,6 +13112,8 @@ F:	fs/kernfs/
 F:	include/linux/kernfs.h
 
 KEXEC
+M:	Andrew Morton <akpm@linux-foundation.org>
+M:	Baoquan He <bhe@redhat.com>
 L:	kexec@lists.infradead.org
 W:	http://kernel.org/pub/linux/utils/kernel/kexec/
 F:	include/linux/kexec.h