MAINTAINERS: add include files to virtio-serial entry

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 4c46cfe..d2f4a11 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -696,6 +696,7 @@
 S: Supported
 F: hw/char/virtio-serial-bus.c
 F: hw/char/virtio-console.c
+F: include/hw/virtio/virtio-serial.h
 
 virtio-rng
 M: Amit Shah <amit.shah@redhat.com>