common: Move get_tbclk() to time.h

This function related to timer and most of the timer functions are in
time.h, so move this function there.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/cpu/mpc85xx/cpu.c b/arch/powerpc/cpu/mpc85xx/cpu.c
index 1855662..9f9eed1 100644
--- a/arch/powerpc/cpu/mpc85xx/cpu.c
+++ b/arch/powerpc/cpu/mpc85xx/cpu.c
@@ -12,6 +12,7 @@
 #include <common.h>
 #include <cpu_func.h>
 #include <irq_func.h>
+#include <time.h>
 #include <vsprintf.h>
 #include <watchdog.h>
 #include <command.h>
@@ -332,7 +333,7 @@
 #ifndef CONFIG_SYS_FSL_TBCLK_DIV
 #define CONFIG_SYS_FSL_TBCLK_DIV 8
 #endif
-__weak unsigned long get_tbclk (void)
+__weak unsigned long get_tbclk(void)
 {
 	unsigned long tbclk_div = CONFIG_SYS_FSL_TBCLK_DIV;