ARMV7/Vexpress: add missing get_ticks() and get_tbclk()

commit f31a911fe (arm, post: add missing post_time_ms for arm)
enables get_ticks and get_tbclk for all arm based boards,
arm/vexpress also needs these functions to work.

Signed-off-by: Liming Wang <walimisdev@gmail.com>
Acked-by: Matt.Waddel@linaro.org

board/armltd/vexpress/ca9x4_ct_vxp.c

@@ -226,3 +226,13 @@ void lowlevel_init(void)
 ulong get_board_rev(void){
 	return readl((u32 *)SYS_ID);
 }
+
+unsigned long long get_ticks(void)
+{
+	return get_timer(0);
+}
+
+ulong get_tbclk (void)
+{
+	return (ulong)CONFIG_SYS_HZ;
+}