ath10k: rename board_data in struct ath10k

I will use board_data for something else in the following patch
so I need to rename it.

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index d5da8a9..90d9399 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -347,7 +347,7 @@
 		} fw;
 	} hw_params;
 
-	const struct firmware *board_data;
+	const struct firmware *board;
 	const struct firmware *otp;
 	const struct firmware *firmware;