clk: Add directory for STM32 clock drivers

Add a directory in drivers/clk to regroup the clock drivers for all
STM32 Soc with CONFIG_ARCH_STM32 (MCUs with cortex M) or
CONFIG_ARCH_STM32MP (MPUs with cortex A).

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Grzegorz Szymaszek <gszymaszek@short.pl>
Acked-by: Sean Anderson <seanga2@gmail.com>
Change-Id: I955af307963f732167396f0157a30cf2fc91f150
diff --git a/MAINTAINERS b/MAINTAINERS
index 1ba36b6..ff59962 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -491,7 +491,7 @@
 F:	arch/arm/mach-stm32mp/
 F:	doc/board/st/
 F:	drivers/adc/stm32-adc*
-F:	drivers/clk/clk_stm32mp1.c
+F:	drivers/clk/stm32/
 F:	drivers/gpio/stm32_gpio.c
 F:	drivers/hwspinlock/stm32_hwspinlock.c
 F:	drivers/i2c/stm32f7_i2c.c