iwlagn: add offset define for subsystem id

Add offset define for subsystem id in EEPROM

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-eeprom.h b/drivers/net/wireless/iwlwifi/iwl-eeprom.h
index 19058a6..c1a17f9 100644
--- a/drivers/net/wireless/iwlwifi/iwl-eeprom.h
+++ b/drivers/net/wireless/iwlwifi/iwl-eeprom.h
@@ -268,6 +268,7 @@
 
 /* General */
 #define EEPROM_DEVICE_ID                    (2*0x08)	/* 2 bytes */
+#define EEPROM_SUBSYSTEM_ID		    (2*0x0A)	/* 2 bytes */
 #define EEPROM_MAC_ADDRESS                  (2*0x15)	/* 6  bytes */
 #define EEPROM_BOARD_REVISION               (2*0x35)	/* 2  bytes */
 #define EEPROM_BOARD_PBA_NUMBER             (2*0x3B+1)	/* 9  bytes */