MAINTAINERS: add missing STM32 entry

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alistair Francis <alistair@alistair23.me>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/MAINTAINERS b/MAINTAINERS
index 8593bfa..09e8e96 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -552,6 +552,7 @@
 F: hw/timer/stm32f2xx_timer.c
 F: hw/adc/*
 F: hw/ssi/stm32f2xx_spi.c
+F: include/hw/*/stm32*.h
 
 Netduino 2
 M: Alistair Francis <alistair@alistair23.me>