arm: rmobile: koelsch: Update calculation of CONFIG_SH_TMU_CLK_FREQ

CONFIG_SH_TMU_CLK_FREQ of koelsch is calculated from the external clock.
This defines RMOBILE_XTAL_CLK, this updates the calculation of
CONFIG_SH_TMU_CLK_FREQ.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/include/configs/koelsch.h b/include/configs/koelsch.h
index 7db6086..1a93d17 100644
--- a/include/configs/koelsch.h
+++ b/include/configs/koelsch.h
@@ -135,8 +135,9 @@
 #define CONFIG_SH_ETHER_ALIGNE_SIZE 64
 
 /* Board Clock */
-#define	CONFIG_SYS_CLK_FREQ	10000000
-#define CONFIG_SH_TMU_CLK_FREQ	CONFIG_SYS_CLK_FREQ
+#define RMOBILE_XTAL_CLK	20000000u
+#define CONFIG_SYS_CLK_FREQ	RMOBILE_XTAL_CLK
+#define CONFIG_SH_TMU_CLK_FREQ	(CONFIG_SYS_CLK_FREQ / 2)
 #define CONFIG_SH_SCIF_CLK_FREQ	14745600
 #define CONFIG_SYS_TMU_CLK_DIV	4