ath9k: remove ath9k 25 MHz HT40 spacing stuff

This was for supporting 25 MHz spacing for HT40, this is not used
as we use 20 MHz spacing instead for HT40 as per 802.11n. The hardware
is capable of it though so we leave the phymode definition and EEPROM
parsing for it. If some experimenter wants to work on this stuff stuff
you can add an extension enabling bool on ath_common and perhaps some
debugfs knob to enable it. Keep in mind you'll also need to update the
phymode with the AR_PHY_FC_DYN2040_EXT_CH which has been left on the
driver.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/phy.h

@@ -45,6 +45,7 @@ bool ath9k_hw_init_rf(struct ath_hw *ah,
 #define AR_PHY_FC_DYN2040_EN        0x00000004
 #define AR_PHY_FC_DYN2040_PRI_ONLY  0x00000008
 #define AR_PHY_FC_DYN2040_PRI_CH    0x00000010
+/* For 25 MHz channel spacing -- not used but supported by hw */
 #define AR_PHY_FC_DYN2040_EXT_CH    0x00000020
 #define AR_PHY_FC_HT_EN             0x00000040
 #define AR_PHY_FC_SHORT_GI_40       0x00000080