arm: rmobile: kzm9g: Add CONFIG_GLOBAL_TIMER to board config file

kzm9g board use global timer. But by commit 813ffda31, timer function of
rmobile was changed that global timer might be used, when CONFIG_GLOBAL_TIMER
was defined.
This add CONFIG_GLOBAL_TIMER to board config file.
Signed-off-by: NNobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: NNobuhiro Iwamatsu <iwamatsu@nigauri.org>

include/configs/kzm9g.h

@@ -135,6 +135,7 @@
 #define CONFIG_SH_GPIO_PFC
 
 /* Clock */
+#define CONFIG_GLOBAL_TIMER
 #define CONFIG_SYS_CLK_FREQ	(48000000)
 #define CONFIG_SYS_CPU_CLK	(1196000000)
 #define TMU_CLK_DIVIDER		(4)	/* 4 (default), 16, 64, 256 or 1024 */