configs: set CONFIG_COUNTER_FREQUENCY

Set CONFIG_COUNTER_FREQUENCY according to COUNTER_FREQUENCY in
config header file.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
[trini: Re-run migration]
diff --git a/configs/firefly-px30_defconfig b/configs/firefly-px30_defconfig
index 873b34b..01858a6 100644
--- a/configs/firefly-px30_defconfig
+++ b/configs/firefly-px30_defconfig
@@ -1,5 +1,6 @@
 CONFIG_ARM=y
 CONFIG_SKIP_LOWLEVEL_INIT=y
+CONFIG_COUNTER_FREQUENCY=24000000
 CONFIG_ARCH_ROCKCHIP=y
 CONFIG_SYS_TEXT_BASE=0x00200000
 CONFIG_SYS_MALLOC_F_LEN=0x2000