ITE boards/it8xxx2_evb/defconfig: use default clock setting

Use default system clock setting 32768 in
soc/riscv/risc-ite/it8xxx2/Kconfig.

Signed-off-by: Ruibin Chang <ruibin.chang@ite.com.tw>
diff --git a/boards/riscv/it8xxx2_evb/it8xxx2_evb_defconfig b/boards/riscv/it8xxx2_evb/it8xxx2_evb_defconfig
index 4fde079..817c640 100644
--- a/boards/riscv/it8xxx2_evb/it8xxx2_evb_defconfig
+++ b/boards/riscv/it8xxx2_evb/it8xxx2_evb_defconfig
@@ -19,7 +19,6 @@
 CONFIG_WDT_ITE_IT8XXX2=y
 
 CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=32768
-CONFIG_SYS_CLOCK_TICKS_PER_SEC=1000
 
 CONFIG_XIP=y
 CONFIG_INIT_STACKS=y