ath9k: Use static const

Using static const generally increases object text and decreases data size.
It also generally decreases overall object size.

   text	   data	    bss	    dec	    hex	filename
  11161	     56	   2136	  13353	   3429	drivers/net/wireless/ath/ath9k/ar9003_paprd.o.new
  11167	     56	   2136	  13359	   342f	drivers/net/wireless/ath/ath9k/ar9003_paprd.o.old
  15428	     56	   3056	  18540	   486c	drivers/net/wireless/ath/ath9k/eeprom_4k.o.old
  15451	     56	   3056	  18563	   4883	drivers/net/wireless/ath/ath9k/eeprom_4k.o.new
  14087	     56	   2560	  16703	   413f	drivers/net/wireless/ath/ath9k/eeprom_9287.o.old
  14036	     56	   2560	  16652	   410c	drivers/net/wireless/ath/ath9k/eeprom_9287.o.new
  10041	     56	   2384	  12481	   30c1	drivers/net/wireless/ath/ath9k/ani.o.new
  10088	     56	   2384	  12528	   30f0	drivers/net/wireless/ath/ath9k/ani.o.old
   9316	   1580	   2304	  13200	   3390	drivers/net/wireless/ath/ath9k/htc_drv_init.o.new
   9316	   1580	   2304	  13200	   3390	drivers/net/wireless/ath/ath9k/htc_drv_init.o.old
  16483	     56	   3432	  19971	   4e03	drivers/net/wireless/ath/ath9k/ar9003_phy.o.new
  16517	     56	   3432	  20005	   4e25	drivers/net/wireless/ath/ath9k/ar9003_phy.o.old
  18221	    104	   2960	  21285	   5325	drivers/net/wireless/ath/ath9k/rc.o.old
  18203	    104	   2960	  21267	   5313	drivers/net/wireless/ath/ath9k/rc.o.new
  19985	     56	   4288	  24329	   5f09	drivers/net/wireless/ath/ath9k/eeprom_def.o.new
  20040	     56	   4288	  24384	   5f40	drivers/net/wireless/ath/ath9k/eeprom_def.o.old
  23997	     56	   4984	  29037	   716d	drivers/net/wireless/ath/ath9k/ar5008_phy.o.old
  23846	     56	   4984	  28886	   70d6	drivers/net/wireless/ath/ath9k/ar5008_phy.o.new
  24285	     56	   3184	  27525	   6b85	drivers/net/wireless/ath/ath9k/ar9003_eeprom.o.old
  24101	     56	   3184	  27341	   6acd	drivers/net/wireless/ath/ath9k/ar9003_eeprom.o.new
   6834	     56	   1032	   7922	   1ef2	drivers/net/wireless/ath/ath9k/ar9002_phy.o.old
   6780	     56	   1032	   7868	   1ebc	drivers/net/wireless/ath/ath9k/ar9002_phy.o.new
  36211	     64	   8624	  44899	   af63	drivers/net/wireless/ath/ath9k/hw.o.new
  36401	     64	   8624	  45089	   b021	drivers/net/wireless/ath/ath9k/hw.o.old
   9281	     56	   1496	  10833	   2a51	drivers/net/wireless/ath/ath9k/ar9003_calib.o.old
   9150	     56	   1496	  10702	   29ce	drivers/net/wireless/ath/ath9k/ar9003_calib.o.new

Use ARRAY_SIZE instead of a magic number.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>