ath5k: fix antenna div gc for <= AR5K_SREV_PHY_2413

In commit 39d5b2c8 "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.

Signed-off-by: Bruno Randolf <br1@einfach.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>