b43: fix extpa_gain check for 2GHz

On the 2GHz and and on the 5GHZ band only the extpa_gain setting from
the 5GHz band was checked. this patch makes it check the property from
the correct band.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
diff --git a/drivers/net/wireless/b43/tables_nphy.c b/drivers/net/wireless/b43/tables_nphy.c
index 25d1cbd..b2f0d24 100644
--- a/drivers/net/wireless/b43/tables_nphy.c
+++ b/drivers/net/wireless/b43/tables_nphy.c
@@ -3728,7 +3728,7 @@
 		switch (phy->rev) {
 		case 6:
 		case 5:
-			if (sprom->fem.ghz5.extpa_gain == 3)
+			if (sprom->fem.ghz2.extpa_gain == 3)
 				return b43_ntab_tx_gain_epa_rev3_hi_pwr_2g;
 			/* fall through */
 		case 4: