timer: stm32: Add timer support for STM32 SoCs family

This timer driver is using GPT Timer (General Purpose Timer)
available on all STM32 SOCs family.
This driver can be used on STM32F4/F7 and H7 SoCs family

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
index 15e5154..a6e7832 100644
--- a/drivers/timer/Makefile
+++ b/drivers/timer/Makefile
@@ -16,3 +16,4 @@
 obj-$(CONFIG_ATCPIT100_TIMER) += atcpit100_timer.o
 obj-$(CONFIG_ROCKCHIP_TIMER) += rockchip_timer.o
 obj-$(CONFIG_ATMEL_PIT_TIMER) += atmel_pit_timer.o
+obj-$(CONFIG_STM32_TIMER)	+= stm32_timer.o