drivers/net/wireless/ath9k: fix sparse warnings: make symbols static

drivers/net/wireless/ath9k: fix sparse warnings: make symbols static

Fix this sparse warnings:

  drivers/net/wireless/ath9k/eeprom.c:195:6: warning: symbol 'ath9k_fill_eeprom' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:463:5: warning: symbol 'ath9k_check_eeprom' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:1219:6: warning: symbol 'ath9k_hw_set_def_power_per_rate_table' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:1510:6: warning: symbol 'ath9k_hw_set_4k_power_per_rate_table' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:2007:5: warning: symbol 'ath9k_set_txpower' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:2106:6: warning: symbol 'ath9k_set_addac' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:2543:6: warning: symbol 'ath9k_eeprom_set_board_values' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:2606:5: warning: symbol 'ath9k_get_eeprom_antenna_cfg' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:2622:4: warning: symbol 'ath9k_hw_get_4k_num_ant_config' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:2628:4: warning: symbol 'ath9k_hw_get_def_num_ant_config' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:2647:4: warning: symbol 'ath9k_get_num_ant_config' was not declared. Should it be static?
  drivers/net/wireless/ath9k/eeprom.c:2790:5: warning: symbol 'ath9k_get_eeprom' was not declared. Should it be static?

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: David S. Miller <davem@davemloft.net>