serial: sh: Drop RTS7751R2D support

There is no RTS7751R2D support in U-Boot, drop all the RTS7751R2D macros.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Chris Brandt <chris.brandt@renesas.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Yoshihiro Shimoda <shimoda.yoshihiro.uh@renesas.com>
diff --git a/drivers/serial/serial_sh.h b/drivers/serial/serial_sh.h
index f78d248..7187e6e 100644
--- a/drivers/serial/serial_sh.h
+++ b/drivers/serial/serial_sh.h
@@ -43,11 +43,6 @@
 # define PORT_PTCR	   0xA405011EUL
 # define PORT_PVCR	   0xA4050122UL
 # define SCIF_ORER	   0x0200   /* overrun error bit */
-#elif defined(CONFIG_SH_RTS7751R2D)
-# define SCSPTR1 0xFFE0001C /* 8 bit SCIF */
-# define SCSPTR2 0xFFE80020 /* 16 bit SCIF */
-# define SCIF_ORER 0x0001   /* overrun error bit */
-# define SCSCR_INIT(port) 0x3a /* TIE=0,RIE=0,TE=1,RE=1,REIE=1 */
 #elif defined(CONFIG_CPU_SH7750)  || \
 	defined(CONFIG_CPU_SH7750R) || \
 	defined(CONFIG_CPU_SH7750S) || \