stm32: clk: Add 200MHz clock configuration for stm32f746 discovery board

This patch adds 200MHz clock configuration for stm32f746 discovery board.
This patch is based on STM32F4 and emcraft's[1].

[1]:  https://github.com/EmcraftSystems/u-boot

Signed-off-by: Toshifumi NISHINAGA <tnishinaga.dev@gmail.com>
diff --git a/arch/arm/mach-stm32/stm32f7/Makefile b/arch/arm/mach-stm32/stm32f7/Makefile
index 40f1ad3..643d4d9 100644
--- a/arch/arm/mach-stm32/stm32f7/Makefile
+++ b/arch/arm/mach-stm32/stm32f7/Makefile
@@ -5,4 +5,4 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-obj-y += timer.o clock.o
+obj-y += timer.o clock.o soc.o