timer: MediaTek: add timer driver for MediaTek SoCs

This patch adds clock source and clock event for the timer found
on the Mediatek SoCs.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Tested-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
index 7f19c49..c4fbab2 100644
--- a/drivers/timer/Makefile
+++ b/drivers/timer/Makefile
@@ -18,3 +18,4 @@
 obj-$(CONFIG_STI_TIMER)		+= sti-timer.o
 obj-$(CONFIG_STM32_TIMER)	+= stm32_timer.o
 obj-$(CONFIG_X86_TSC_TIMER)	+= tsc_timer.o
+obj-$(CONFIG_MTK_TIMER)		+= mtk_timer.o