sc16is7xx: fix incorrect register bits macro

In datasheet, Modem Status Register MSR[4-7] reflect the modem pins
CTS/DSR/RI/CD signal state.
Signed-off-by: Wills Wang <wills.wang@live.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/sc16is7xx.c

@@ -196,14 +196,14 @@
 						  * or (IO6)
 						  * - only on 75x/76x
 						  */
-#define SC16IS7XX_MSR_CTS_BIT		(1 << 0) /* CTS */
-#define SC16IS7XX_MSR_DSR_BIT		(1 << 1) /* DSR (IO4)
+#define SC16IS7XX_MSR_CTS_BIT		(1 << 4) /* CTS */
+#define SC16IS7XX_MSR_DSR_BIT		(1 << 5) /* DSR (IO4)
 						  * - only on 75x/76x
 						  */
-#define SC16IS7XX_MSR_RI_BIT		(1 << 2) /* RI (IO7)
+#define SC16IS7XX_MSR_RI_BIT		(1 << 6) /* RI (IO7)
 						  * - only on 75x/76x
 						  */
-#define SC16IS7XX_MSR_CD_BIT		(1 << 3) /* CD (IO6)
+#define SC16IS7XX_MSR_CD_BIT		(1 << 7) /* CD (IO6)
 						  * - only on 75x/76x
 						  */
 #define SC16IS7XX_MSR_DELTA_MASK	0x0F     /* Any of the delta bits! */
@@ -240,7 +240,7 @@
 
 /* IOControl register bits (Only 750/760) */
 #define SC16IS7XX_IOCONTROL_LATCH_BIT	(1 << 0) /* Enable input latching */
-#define SC16IS7XX_IOCONTROL_GPIO_BIT	(1 << 1) /* Enable GPIO[7:4] */
+#define SC16IS7XX_IOCONTROL_MODEM_BIT	(1 << 1) /* Enable GPIO[7:4] as modem pins */
 #define SC16IS7XX_IOCONTROL_SRESET_BIT	(1 << 3) /* Software Reset */
 
 /* EFCR register bits */
@@ -687,7 +687,7 @@ static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
 		case SC16IS7XX_IIR_CTSRTS_SRC:
 			msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
 			uart_handle_cts_change(port,
-					       !!(msr & SC16IS7XX_MSR_CTS_BIT));
+					       !!(msr & SC16IS7XX_MSR_DCTS_BIT));
 			break;
 		case SC16IS7XX_IIR_THRI_SRC:
 			sc16is7xx_handle_tx(port);