rt2x00: Fix RT3572 channel switch RFCSR 7 programming.

Align with the v2.5.0.0 Ralink RT3572 driver.
Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2800.h

@@ -1819,10 +1819,12 @@ struct mac_iveiv_entry {
  * RFCSR 7:
  */
 #define RFCSR7_RF_TUNING		FIELD8(0x01)
-#define RFCSR7_R02				FIELD8(0x07)
-#define RFCSR7_R3				FIELD8(0x08)
-#define RFCSR7_R45				FIELD8(0x30)
-#define RFCSR7_R67				FIELD8(0xc0)
+#define RFCSR7_BIT1			FIELD8(0x02)
+#define RFCSR7_BIT2			FIELD8(0x04)
+#define RFCSR7_BIT3			FIELD8(0x08)
+#define RFCSR7_BIT4			FIELD8(0x10)
+#define RFCSR7_BIT5			FIELD8(0x20)
+#define RFCSR7_BITS67			FIELD8(0xc0)
 
 /*
  * RFCSR 11:

drivers/net/wireless/rt2x00/rt2800lib.c

@@ -1865,7 +1865,12 @@ static void rt2800_config_channel_rf3052(struct rt2x00_dev *rt2x00dev,
 		rt2800_rfcsr_write(rt2x00dev, 27, 0x00);
 		rt2800_rfcsr_write(rt2x00dev, 29, 0x9b);
 	} else {
-		rt2800_rfcsr_write(rt2x00dev, 7, 0x14);
+		rt2800_rfcsr_read(rt2x00dev, 7, &rfcsr);
+		rt2x00_set_field8(&rfcsr, RFCSR7_BIT2, 1);
+		rt2x00_set_field8(&rfcsr, RFCSR7_BIT3, 0);
+		rt2x00_set_field8(&rfcsr, RFCSR7_BIT4, 1);
+		rt2x00_set_field8(&rfcsr, RFCSR7_BITS67, 0);
+		rt2800_rfcsr_write(rt2x00dev, 7, rfcsr);
 		rt2800_rfcsr_write(rt2x00dev, 9, 0xc0);
 		rt2800_rfcsr_write(rt2x00dev, 10, 0xf1);
 		rt2800_rfcsr_write(rt2x00dev, 11, 0x00);