MAINTAINERS: add Jann as memory mapping/VMA reviewer

Add myself as a reviewer for memory mapping / VMA code.  I will probably
only reply to patches sporadically, but hopefully this will help me keep
up with changes that look interesting security-wise.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Jann Horn <[email protected]>
Acked-by: Liam R. Howlett <[email protected]>
Acked-by: Lorenzo Stoakes <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: thejh

MAINTAINERS

@@ -14912,6 +14912,7 @@ M:	Andrew Morton <[email protected]>
 M:	Liam R. Howlett <[email protected]>
 M:	Lorenzo Stoakes <[email protected]>
 R:	Vlastimil Babka <[email protected]>
+R:	Jann Horn <[email protected]>
 L:	[email protected]
 S:	Maintained
 W:	http://www.linux-mm.org
@@ -24742,6 +24743,7 @@ M:	Andrew Morton <[email protected]>
 M:	Liam R. Howlett <[email protected]>
 M:	Lorenzo Stoakes <[email protected]>
 R:	Vlastimil Babka <[email protected]>
+R:	Jann Horn <[email protected]>
 L:	[email protected]
 S:	Maintained
 W:	https://www.linux-mm.org