sh: timer: Change definition of clock of TMU

The former SH/TMU driver had calculated timer based on CONFIG_SYS_CLK_FREQ.
The newest SH/TMU newly needs calculation of the clock for TMU.
This patch defines clock CONFIG_SH_TMU_CLK_FREQ for TMU and changes it to
CONFIG_SH_TMU_CLK_FREQ from CONFIG_SYS_CLK_FREQ.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

include/sh_tmu.h

@@ -69,7 +69,7 @@ struct tmu_regs {
 
 static inline unsigned long get_tmu0_clk_rate(void)
 {
-	return CONFIG_SYS_CLK_FREQ;
+	return CONFIG_SH_TMU_CLK_FREQ;
 }
 
 #endif	/* __SH_TMU_H */