nios2: convert altera timer to driver model

Convert altera timer to driver model.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Acked-by: Chin Liang See <clsee@altera.com>
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig
index 8e8d600..97c4128 100644
--- a/drivers/timer/Kconfig
+++ b/drivers/timer/Kconfig
@@ -9,4 +9,11 @@
 	  will be used. The timer is usually a 32 bits free-running up
 	  counter. There may be no real tick, and no timer interrupt.
 
+config ALTERA_TIMER
+	bool "Altera Timer support"
+	depends on TIMER
+	help
+	  Select this to enable an timer for Altera devices. Please find
+	  details on the "Embedded Peripherals IP User Guide" of Altera.
+
 endmenu