serial: sh: Change definition of clock of SCIF

The former SH/SCIF driver had calculated baudrate based on CONFIG_SYS_CLK_FREQ.
The newest SH/SCIF needs calculation of the clock for SCIF.
This patch defines clock CONFIG_SH_SCIF_CLK_FREQ for SCIF and changes it to
CONFIG_SH_SCIF_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>
CC: Albert Aribaud <albert.u.boot@aribaud.net>

drivers/serial/serial_sh.c

@@ -48,7 +48,9 @@ static struct uart_port sh_sci = {
 static void sh_serial_setbrg(void)
 {
 	DECLARE_GLOBAL_DATA_PTR;
-	sci_out(&sh_sci, SCBRR, SCBRR_VALUE(gd->baudrate, CONFIG_SYS_CLK_FREQ));
+
+	sci_out(&sh_sci, SCBRR,
+		SCBRR_VALUE(gd->baudrate, CONFIG_SH_SCIF_CLK_FREQ));
 }
 
 static int sh_serial_init(void)