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/common/board_f.c b/common/board_f.c
index 8bb8ded..613332e 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -795,8 +795,7 @@
 	init_timebase,
 #endif
 #if defined(CONFIG_ARM) || defined(CONFIG_MIPS) || \
-		defined(CONFIG_BLACKFIN) || defined(CONFIG_NDS32) || \
-		defined(CONFIG_NIOS2)
+		defined(CONFIG_BLACKFIN) || defined(CONFIG_NDS32)
 	timer_init,		/* initialize timer */
 #endif
 #ifdef CONFIG_SYS_ALLOC_DPRAM