riscv: Move Andes PLMT driver to drivers/timer

This is a regular timer driver, and should live with the other timer
drivers.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Rick Chen <rick@andestech.com>
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig
index f8fa4aa..6b8e4c9 100644
--- a/drivers/timer/Kconfig
+++ b/drivers/timer/Kconfig
@@ -53,6 +53,13 @@
 	  Select this to enable a timer for Altera devices. Please find
 	  details on the "Embedded Peripherals IP User Guide" of Altera.
 
+config ANDES_PLMT
+	bool
+	depends on RISCV_MMODE || SPL_RISCV_MMODE
+	help
+	  The Andes PLMT block holds memory-mapped mtime register
+	  associated with timer tick.
+
 config ARC_TIMER
 	bool "ARC timer support"
 	depends on TIMER && ARC && CLK