feat(ast2700): set up CPU clock frequency by SCU

Modify generic timer frequency by SCU setting
1. check SCU_CPU_HW_STRAP1 using HPLL or MPLL
  SCU_CPU_HW_STRAP1[4]=1, using HPLL
  SCU_CPU_HW_STRAP1[4]=0, using MPLL

2. read HPLL or MPLL
  HPLL: frequency setting in SCU_CPU_HW_STRAP1[2:3]
  MPLL: CLKIN_25M with mul and div setting from SCU_CPU_MPLL

Change-Id: I31eb10107b9da7c6746887ba36ead8ca61d86aae
Signed-off-by: Kevin Chen <kevin_chen@aspeedtech.com>
diff --git a/plat/aspeed/ast2700/include/platform_reg.h b/plat/aspeed/ast2700/include/platform_reg.h
index 7f26865..3c164a4 100644
--- a/plat/aspeed/ast2700/include/platform_reg.h
+++ b/plat/aspeed/ast2700/include/platform_reg.h
@@ -19,6 +19,10 @@
 
 /* CPU-die SCU */
 #define SCU_CPU_BASE	U(0x12c02000)
+#define SCU_CPU_HW_STRAP1	(SCU_CPU_BASE + 0x010)
+#define SCU_CPU_HPLL	(SCU_CPU_BASE + 0x300)
+#define SCU_CPU_DPLL	(SCU_CPU_BASE + 0x308)
+#define SCU_CPU_MPLL	(SCU_CPU_BASE + 0x310)
 #define SCU_CPU_SMP_EP0	(SCU_CPU_BASE + 0x780)
 #define SCU_CPU_SMP_EP1	(SCU_CPU_BASE + 0x788)
 #define SCU_CPU_SMP_EP2	(SCU_CPU_BASE + 0x790)