ath9k: change entropy formula for easier understanding

The quality of ADC entropy is 10 bits of min-entropy for
a 32-bit value, change '(((x) * 8 * 320) >> 10)' to
'(((x) * 8 * 10) >> 5)' for easier understanding.
Signed-off-by: NMiaoqing Pan <miaoqing@codeaurora.org>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath9k/rng.c

@@ -22,7 +22,7 @@
 #include "ar9003_phy.h"
 
 #define ATH9K_RNG_BUF_SIZE	320
-#define ATH9K_RNG_ENTROPY(x)	(((x) * 8 * 320) >> 10) /* quality: 320/1024 */
+#define ATH9K_RNG_ENTROPY(x)	(((x) * 8 * 10) >> 5) /* quality: 10/32 */
 
 static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
 {