ath9k: Fix incorrect access of rate flags in RC

ath9k: Fix incorrect access of rate flags in RC

commit 4fc4fbd1d9a05fa4f348b499aca3a6f8d3c9bbe6 upstream.

The index variable to access the rate flags should be obtained from the
inner loop counter which corresponds to the rate table structure.This
fixes the invalid rate selection i.e when the supported basic rate is
invalid on a particular band and also the following warning message.
Thanks to Raj for finding this out.

Call Trace:

 [<ffffffff8104ee4a>] warn_slowpath_common+0x7a/0xb0

 [<ffffffff8104ee95>] warn_slowpath_null+0x15/0x20

 [<ffffffffa0583c45>] ath_get_rate+0x595/0x5b0 [ath9k]

 [<ffffffff811a0636>] ? cpumask_next_and+0x36/0x50

 [<ffffffffa0405186>] rate_control_get_rate+0x86/0x160 [mac80211]

 [<ffffffffa040dfac>] invoke_tx_handlers+0x81c/0x12d0 [mac80211]

 [<ffffffffa040eae9>] ieee80211_tx+0x89/0x2b0 [mac80211]

 [<ffffffff812891bc>] ? pskb_expand_head+0x1cc/0x1f0

 [<ffffffffa040edc5>] ieee80211_xmit+0xb5/0x1c0 [mac80211]

 [<ffffffffa041026f>] ieee80211_tx_skb+0x4f/0x60 [mac80211]

 [<ffffffffa03fe016>] ieee80211_send_nullfunc+0x46/0x60 [mac80211]

 [<ffffffffa03f91d7>] ieee80211_offchannel_stop_station+0x107/0x150
[mac80211]

 [<ffffffff812891bc>] ? pskb_expand_head+0x1cc/0x1f0

 [<ffffffffa040edc5>] ieee80211_xmit+0xb5/0x1c0 [mac80211]

 [<ffffffffa041026f>] ieee80211_tx_skb+0x4f/0x60 [mac80211]

 [<ffffffffa03fe016>] ieee80211_send_nullfunc+0x46/0x60 [mac80211]

 [<ffffffffa03f91d7>] ieee80211_offchannel_stop_station+0x107/0x150
[mac80211]

 [<ffffffffa03f8896>] ieee80211_scan_work+0x146/0x600 [mac80211]

 [<ffffffff8133a375>] ? schedule+0x2f5/0x8e0

 [<ffffffffa03f8750>] ? ieee80211_scan_work+0x0/0x600 [mac80211]

 [<ffffffff81064fcf>] process_one_work+0x10f/0x380

 [<ffffffff81066bc2>] worker_thread+0x162/0x340

 [<ffffffff81066a60>] ? worker_thread+0x0/0x340

Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>