ath9k: Fix a smatch warnings

Smatch shows the following warnings:

  CHECK   drivers/net/wireless/ath/ath9k/htc_drv_main.c
drivers/net/wireless/ath/ath9k/htc_drv_main.c +1315 ath9k_htc_configure_filter(27) warn: inconsistent returns mutex:&priv->mutex: locked (1303) unlocked (1315)

  CHECK   drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
drivers/net/wireless/ath/ath9k/ar9003_eeprom.c +3321 ar9300_eeprom_restore_internal(20) warn: returning -1 instead of -ENOMEM is sloppy

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>