timer: Add AST2700 IBEX timer support

Add the driver for the AST2700 Ibex timer, which uses CPU
cycles as the timer count running at 200MHz.

Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig
index 6b1de82..cb6fc0e 100644
--- a/drivers/timer/Kconfig
+++ b/drivers/timer/Kconfig
@@ -106,6 +106,12 @@
 	  This is mostly because they all share several registers which
 	  makes it difficult to completely separate them.
 
+config AST_IBEX_TIMER
+	bool "Aspeed ast2700 Ibex timer"
+	depends on TIMER
+	help
+	  Select this to enable a timer support for the Ibex RV32-based MCUs in AST2700.
+
 config ATCPIT100_TIMER
 	bool "ATCPIT100 timer support"
 	depends on TIMER