ath5k: fix antenna div gc for <= AR5K_SREV_PHY_2413

In commit 39d5b2c83ca8904b6826a0713263a4e5a9c0730a "ath5k: update AR5K_PHY_RESTART_DIV_GC values to match masks" i introduced a regression on PHY chips older than AR5K_SREV_PHY_5413, which caused signal values to be about 10dB less that before. This patch reverts the AR5K_PHY_RESTART_DIV_GC values to the same values which were effectively used before (without the bitmask mistake). This brings signal levels back to normal on these PHY chips.

---
 drivers/net/wireless/ath/ath5k/phy.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index 73c4fcd..6284c38 100644
@@ -1768,7 +1768,7 @@ ath5k_hw_set_fast_div(struct ath5k_hw *ah, u8 ee_mode, bool enable)
 
 	if (enable) {
 		AR5K_REG_WRITE_BITS(ah, AR5K_PHY_RESTART,
-				AR5K_PHY_RESTART_DIV_GC, 1);
+				AR5K_PHY_RESTART_DIV_GC, 4);
 
 		AR5K_REG_ENABLE_BITS(ah, AR5K_PHY_FAST_ANT_DIV,
 					AR5K_PHY_FAST_ANT_DIV_EN);