Makefile: Change COUNTER_FREQ to 100 MHz

Older Arm Fast Models (AEM < RevC) had a base frequency of 24 MHz. but
the RevC base models use 100 MHz. There is not a robust method of
determining the configured base frequency at runtime, so update
COUNTER_FREQ to be 100 MHz.

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
diff --git a/Makefile.am b/Makefile.am
index 08e304a..6ebece2 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -13,7 +13,7 @@
 PHYS_OFFSET	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findmem.pl $(KERNEL_DTB))
 UART_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 0 'arm,pl011')
 SYSREGS_BASE	:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findbase.pl $(KERNEL_DTB) 0 'arm,vexpress-sysreg' 2> /dev/null)
-COUNTER_FREQ	:= 24000000
+COUNTER_FREQ	:= 100000000
 
 CPU_IDS		:= $(shell perl -I $(SCRIPT_DIR) $(SCRIPT_DIR)/findcpuids.pl $(KERNEL_DTB))
 NR_CPUS         := $(shell echo $(CPU_IDS) | tr ',' ' ' | wc -w)