MAINTAINERS: Add entry for STM32 MCUs

Add a MAINTAINER entry covering all STM32 machine and drivers files.
Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

MAINTAINERS

@@ -1485,6 +1485,14 @@ F:	drivers/usb/host/ehci-st.c
 F:	drivers/usb/host/ohci-st.c
 F:	drivers/ata/ahci_st.c
 
+ARM/STM32 ARCHITECTURE
+M:	Maxime Coquelin <mcoquelin.stm32@gmail.com>
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+S:	Maintained
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mcoquelin/stm32.git
+N:	stm32
+F:	drivers/clocksource/armv7m_systick.c
+
 ARM/TECHNOLOGIC SYSTEMS TS7250 MACHINE SUPPORT
 M:	Lennert Buytenhek <kernel@wantstofly.org>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)