sh: Fix receive FIFO level register of SH4A

Receive FIFO level register is different in SH4A.
Because register is different, cannot occasionally receive data.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

drivers/serial/serial_sh.c

@@ -53,18 +53,22 @@
 # define SCLSR   (vu_short *)(SCIF_BASE + 0x28)
 # define SCRER	(vu_short *)(SCIF_BASE + 0x2C)
 # define LSR_ORER	1
+# define FIFOLEVEL_MASK	0xFF
 #elif defined(CONFIG_CPU_SH7750) || \
 	defined(CONFIG_CPU_SH7722)
 # define SCSPTR 	(vu_short *)(SCIF_BASE + 0x20)
 # define SCLSR 	(vu_short *)(SCIF_BASE + 0x24)
 # define LSR_ORER	1
+# define FIFOLEVEL_MASK	0x1F
 #elif defined(CONFIG_CPU_SH7720)
 # define SCLSR   (vu_short *)(SCIF_BASE + 0x24)
 # define LSR_ORER	0x0200
+# define FIFOLEVEL_MASK	0x1F
 #elif defined(CONFIG_CPU_SH7710)
 	defined(CONFIG_CPU_SH7712)
 # define SCLSR	SCFSR	/* SCSSR */
 # define LSR_ORER	1
+# define FIFOLEVEL_MASK	0x1F
 #endif
 
 /* SCBRR register value setting */
@@ -109,12 +113,16 @@ int serial_init (void)
 
 static int serial_tx_fifo_level (void)
 {
-	return (*SCFDR >> 8) & 0x1F;
+	return (*SCFDR >> 8) & FIFOLEVEL_MASK;
 }
 
 static int serial_rx_fifo_level (void)
 {
-	return (*SCFDR >> 0) & 0x1F;
+#if defined(CONFIG_SH4A)
+	return (*SCRFDR >> 0) & FIFOLEVEL_MASK;
+#else
+	return (*SCFDR >> 0) & FIFOLEVEL_MASK;
+#endif
 }
 
 void serial_raw_putc (const char c)