ath9k: Remove multiple macro occurrences

OLC_FOR_AR9280_20_LATER is defined in multiple places,
move it to a common location.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath9k/eeprom.h b/drivers/net/wireless/ath9k/eeprom.h
index 2cfea5d..6296e3e 100644
--- a/drivers/net/wireless/ath9k/eeprom.h
+++ b/drivers/net/wireless/ath9k/eeprom.h
@@ -95,6 +95,9 @@
 #define FREQ2FBIN(x, y)		((y) ? ((x) - 2300) : (((x) - 4800) / 5))
 #define ath9k_hw_use_flash(_ah)	(!(_ah->ah_flags & AH_USE_EEPROM))
 
+#define OLC_FOR_AR9280_20_LATER (AR_SREV_9280_20_OR_LATER(ah) && \
+				 ah->eep_ops->get_eeprom(ah, EEP_OL_PWRCTRL))
+
 #define AR_EEPROM_RFSILENT_GPIO_SEL     0x001c
 #define AR_EEPROM_RFSILENT_GPIO_SEL_S   2
 #define AR_EEPROM_RFSILENT_POLARITY     0x0002