Move ICS CLK chip frequency calculation code into a common board library

We have several boards that use the same ICS307 CLK chip to drive the
System clock and DDR clock.  Move the code into a common location so we
share it.

Convert the P2020DS board as the first to use the new common ICS307
code.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Timur Tabi <timur@freescale.com>
diff --git a/include/configs/P2020DS.h b/include/configs/P2020DS.h
index 66be725..9955501 100644
--- a/include/configs/P2020DS.h
+++ b/include/configs/P2020DS.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2007-2009 Freescale Semiconductor, Inc.
+ * Copyright 2007-2010 Freescale Semiconductor, Inc.
  *
  * See file CREDITS for list of people who contributed to this
  * project.
@@ -27,6 +27,8 @@
 #ifndef __CONFIG_H
 #define __CONFIG_H
 
+#include "../board/freescale/common/ics307_clk.h"
+
 #ifdef CONFIG_MK_36BIT
 #define CONFIG_PHYS_64BIT
 #endif
@@ -54,17 +56,9 @@
 #define CONFIG_TSEC_ENET		/* tsec ethernet support */
 #define CONFIG_ENV_OVERWRITE
 
-#ifndef __ASSEMBLY__
-extern unsigned long calculate_board_sys_clk(unsigned long dummy);
-extern unsigned long calculate_board_ddr_clk(unsigned long dummy);
-/* extern unsigned long get_board_sys_clk(unsigned long dummy); */
-/* extern unsigned long get_board_ddr_clk(unsigned long dummy); */
-#endif
-#define CONFIG_SYS_CLK_FREQ	calculate_board_sys_clk(0) /* sysclk for MPC85xx */
-#define CONFIG_DDR_CLK_FREQ	calculate_board_ddr_clk(0) /* ddrclk for MPC85xx */
+#define CONFIG_SYS_CLK_FREQ	get_board_sys_clk() /* sysclk for MPC85xx */
+#define CONFIG_DDR_CLK_FREQ	get_board_ddr_clk() /* ddrclk for MPC85xx */
 #define CONFIG_ICS307_REFCLK_HZ	33333000  /* ICS307 clock chip ref freq */
-#define CONFIG_GET_CLK_FROM_ICS307	  /* decode sysclk and ddrclk freq
-					     from ICS307 instead of switches */
 
 /*
  * These can be toggled for performance analysis, otherwise use default.