Move `plat_get_syscnt_freq()` to arm_common.c

This patch moves the definition for `plat_get_syscnt_freq()`
from arm_bl31_setup.c to arm_common.c. This could be useful
in case a delay timer needs to be installed based on the
generic timer in other BLs.
This patch also modifies the return type for this function
from `uint64_t` to `unsigned long long` within ARM and other
platform files.

Change-Id: Iccdfa811948e660d4fdcaae60ad1d700e4eda80d
diff --git a/plat/arm/common/aarch64/arm_common.c b/plat/arm/common/aarch64/arm_common.c
index 78b75b4..74c65ed 100644
--- a/plat/arm/common/aarch64/arm_common.c
+++ b/plat/arm/common/aarch64/arm_common.c
@@ -29,6 +29,7 @@
  */
 #include <arch.h>
 #include <arch_helpers.h>
+#include <debug.h>
 #include <mmio.h>
 #include <plat_arm.h>
 #include <platform_def.h>
@@ -39,7 +40,7 @@
 /* Weak definitions may be overridden in specific ARM standard platform */
 #pragma weak plat_get_ns_image_entrypoint
 #pragma weak plat_arm_get_mmap
-
+#pragma weak plat_get_syscnt_freq
 
 /*******************************************************************************
  * Macro generating the code for the function setting up the pagetables as per
@@ -161,3 +162,17 @@
 {
 	return plat_arm_mmap;
 }
+
+unsigned long long plat_get_syscnt_freq(void)
+{
+	unsigned long long counter_base_frequency;
+
+	/* Read the frequency from Frequency modes table */
+	counter_base_frequency = mmio_read_32(ARM_SYS_CNTCTL_BASE + CNTFID_OFF);
+
+	/* The first entry of the frequency modes table must not be 0 */
+	if (counter_base_frequency == 0)
+		panic();
+
+	return counter_base_frequency;
+}
diff --git a/plat/arm/common/arm_bl31_setup.c b/plat/arm/common/arm_bl31_setup.c
index 8fcfa77..8eb6818 100644
--- a/plat/arm/common/arm_bl31_setup.c
+++ b/plat/arm/common/arm_bl31_setup.c
@@ -34,7 +34,6 @@
 #include <assert.h>
 #include <bl_common.h>
 #include <console.h>
-#include <debug.h>
 #include <mmio.h>
 #include <plat_arm.h>
 #include <platform.h>
@@ -76,7 +75,6 @@
 #pragma weak bl31_platform_setup
 #pragma weak bl31_plat_arch_setup
 #pragma weak bl31_plat_get_next_image_ep_info
-#pragma weak plat_get_syscnt_freq
 
 
 /*******************************************************************************
@@ -268,17 +266,3 @@
 {
 	arm_bl31_plat_arch_setup();
 }
-
-uint64_t plat_get_syscnt_freq(void)
-{
-	uint64_t counter_base_frequency;
-
-	/* Read the frequency from Frequency modes table */
-	counter_base_frequency = mmio_read_32(ARM_SYS_CNTCTL_BASE + CNTFID_OFF);
-
-	/* The first entry of the frequency modes table must not be 0 */
-	if (counter_base_frequency == 0)
-		panic();
-
-	return counter_base_frequency;
-}