serial: sh-sci: Kill off unused clock string.

Now that the clock string isn't used by the driver anymore, kill it off
from the platform structure.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

include/linux/serial_sci.h

@@ -45,7 +45,6 @@ struct plat_sci_port {
 	unsigned int	irqs[SCIx_NR_IRQS];	/* ERI, RXI, TXI, BRI */
 	unsigned int	type;			/* SCI / SCIF / IRDA */
 	upf_t		flags;			/* UPF_* flags */
-	char		*clk;			/* clock string */
 
 	unsigned int	scbrr_algo_id;		/* SCBRR calculation algo */
 	unsigned int	scscr;			/* SCSCR initialization */