imx: imx8ulp: Set COUNTER_FREQUENCY to 1Mhz

The COUNTER_FREQUENCY is missed in 8ulp configs, it will cause SPL
and u-boot not set the cntfrq_el0. For u-boot, this is ok, because
ATF has set it. But for SPL, it will lead delay and get_timer
not working.

Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/include/configs/imx8ulp_evk.h b/include/configs/imx8ulp_evk.h
index ddb3d44..e688674 100644
--- a/include/configs/imx8ulp_evk.h
+++ b/include/configs/imx8ulp_evk.h
@@ -27,6 +27,8 @@
 
 #endif
 
+#define COUNTER_FREQUENCY		1000000 /* 1MHz */
+
 /* ENET Config */
 #if defined(CONFIG_FEC_MXC)
 #define PHY_ANEG_TIMEOUT		20000