ath9k: simplify ATH_EP_RND

Remove the embedded branch to make the ATH_EP_RND macro a little
clearer.  The new version also generates better code, saving 24
bytes of text:

   text	   data	    bss	    dec	    hex	filename
  87858	   1641	     24	  89523	  15db3	ath9k_orig.ko
  87834	   1641	     24	  89499	  15d9b	ath9k_new.ko

Although neither version handles negative values particularly well,
the lone caller clamps all negative values to zero anyway.  I have
verified that the results are the same for the range of possible
positive rssi values.
Signed-off-by: NBob Copeland <me@bobcopeland.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/common.h

@@ -40,7 +40,7 @@
 	x = ATH_LPF_RSSI((x), ATH_RSSI_IN((y)), ATH_RSSI_LPF_LEN);  	\
 } while (0)
 #define ATH_EP_RND(x, mul) 						\
-	((((x)%(mul)) >= ((mul)/2)) ? ((x) + ((mul) - 1)) / (mul) : (x)/(mul))
+	(((x) + ((mul)/2)) / (mul))
 
 int ath9k_cmn_padpos(__le16 frame_control);
 int ath9k_cmn_get_hw_crypto_keytype(struct sk_buff *skb);