ath5k: Implement antenna control

* Add code to support the various antenna scenarios supported by hw

 * For now hardcode the default scenario (single or dual omnis with
 tx/rx diversity working and tx antenna handled by session -hw keeps
 track on which antenna it got ack from each ap/station and maps each
 ap/station to one of the antennas-).

 Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
 Signed-off-by: Bob Copeland <me@bobcopeland.com>

Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/eeprom.c

@@ -208,16 +208,16 @@ static int ath5k_eeprom_read_ants(struct ath5k_hw *ah, u32 *offset,
 	ee->ee_ant_control[mode][i++]	= (val >> 6) & 0x3f;
 	ee->ee_ant_control[mode][i++]	= val & 0x3f;
 
-	/* Get antenna modes */
-	ah->ah_antenna[mode][0] =
+	/* Get antenna switch tables */
+	ah->ah_ant_ctl[mode][AR5K_ANT_CTL] =
 	    (ee->ee_ant_control[mode][0] << 4);
-	ah->ah_antenna[mode][AR5K_ANT_FIXED_A] =
+	ah->ah_ant_ctl[mode][AR5K_ANT_SWTABLE_A] =
 	     ee->ee_ant_control[mode][1] 	|
 	    (ee->ee_ant_control[mode][2] << 6) 	|
 	    (ee->ee_ant_control[mode][3] << 12) |
 	    (ee->ee_ant_control[mode][4] << 18) |
 	    (ee->ee_ant_control[mode][5] << 24);
-	ah->ah_antenna[mode][AR5K_ANT_FIXED_B] =
+	ah->ah_ant_ctl[mode][AR5K_ANT_SWTABLE_B] =
 	     ee->ee_ant_control[mode][6] 	|
 	    (ee->ee_ant_control[mode][7] << 6) 	|
 	    (ee->ee_ant_control[mode][8] << 12) |