rt2x00: Simplify check for external LNA in rt2800_init_rfcsr.

Instead of parsing the EEPROM information, use the flag that was set during
device initialization.
Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>

drivers/net/wireless/rt2x00/rt2800lib.c

@@ -2072,8 +2072,7 @@ int rt2800_init_rfcsr(struct rt2x00_dev *rt2x00dev)
 	if (rt2x00_rt_rev_lt(rt2x00dev, RT3071, REV_RT3071E) ||
 	    rt2x00_rt_rev_lt(rt2x00dev, RT3090, REV_RT3090E) ||
 	    rt2x00_rt_rev_lt(rt2x00dev, RT3390, REV_RT3390E)) {
-		rt2x00_eeprom_read(rt2x00dev, EEPROM_NIC, &eeprom);
-		if (rt2x00_get_field16(eeprom, EEPROM_NIC_EXTERNAL_LNA_BG))
+		if (test_bit(CONFIG_EXTERNAL_LNA_BG, &rt2x00dev->flags))
 			rt2x00_set_field8(&rfcsr, RFCSR17_R, 1);
 	}
 	rt2x00_eeprom_read(rt2x00dev, EEPROM_TXMIXER_GAIN_BG, &eeprom);