dm: clk: add clk driver support for stm32h7 SoCs

This driver implements basic clock setup, only clock gating
is implemented.

This driver doesn't implement .of_match as it's binded
by MFD RCC driver.

Files include/dt-bindings/clock/stm32h7-clks.h and
doc/device-tree-bindings/clock/st,stm32h7-rcc.txt
will be available soon in a kernel tag, as all the
bindings have been acked by Rob Herring [1].

[1] http://lkml.iu.edu/hypermail/linux/kernel/1704.0/00935.html

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index b773593..83fe88c 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -22,3 +22,4 @@
 obj-$(CONFIG_CLK_BOSTON) += clk_boston.o
 obj-$(CONFIG_ARCH_ASPEED) += aspeed/
 obj-$(CONFIG_STM32F7) += clk_stm32f7.o
+obj-$(CONFIG_STM32H7) += clk_stm32h7.o