This patch fixes a regression introduced by the following patch:
"ar9170: load firmware asynchronously"

When we kick off a firmware loading request and then unbind,
or disconnect the usb device right away, we get into trouble:

> ------------[ cut here ]------------
> WARNING: at lib/kref.c:44 kref_get+0x1c/0x20()
> Hardware name: 18666GU
> Modules linked in: ar9170usb [...]
> Pid: 6588, comm: firmware/ar9170 Not tainted 2.6.34-rc5-wl #43
> Call Trace:
> [<c102b05e>] ? warn_slowpath_common+0x6e/0xb0
> [<c117c93c>] ? kref_get+0x1c/0x20
> [<c102b0b3>] ? warn_slowpath_null+0x13/0x20
> [<c117c93c>] ? kref_get+0x1c/0x20
> [<c117bb2f>] ? kobject_get+0xf/0x20
> [<c124d630>] ? get_device+0x10/0x20
> [<c124e5a0>] ? device_add+0x60/0x530
> [<c117b8b5>] ? kobject_init+0x25/0xa0
> [<c12569f9>] ? _request_firmware+0x139/0x3e0
> [<c1256cc0>] ? request_firmware_work_func+0x20/0x70
> [<c1256ca0>] ? request_firmware_work_func+0x0/0x70
> [<c103ff24>] ? kthread+0x74/0x80
> [<c103feb0>] ? kthread+0x0/0x80
> [<c1003136>] ? kernel_thread_helper+0x6/0x10
>---[ end trace 2d50bd818f64a1b7 ]---
- followed by a random Oops -

Avoid that by waiting for the firmware loading to finish
(whether successfully or not) before the unbind in
ar9170_usb_disconnect.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Bug-fixed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Some firmware versions don't behave properly when
passive scanning is requested on radar channels
without enabling active scanning on receiving a
good frame. Work around that issue by asking the
firmware to only enable the active scanning after
receiving a huge number of good frames, a number
that can never be reached during our dwell time.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

Hans de Goede identified a bug in p54p_check_tx_ring:

there are two ring indices. 1 => tx data and 3 => tx management.
But the old code had a constant "1" and this resulted in spurious
dma unmapping failures.

Cc: stable@kernel.org
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=583623
Bug-Identified-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

For 6000 series, the 2.4G HT40 band regulatory settings address in EEPROM
was off by 2.

Before the fix, you'll see this in dmesg:
[79535.788877] ieee80211 phy8: U iwl_mod_ht40_chan_info HT40 Ch. 7 [2.4GHz]
WIDE (0x61 0dBm): Ad-Hoc not supported
[79535.788880] ieee80211 phy8: U iwl_mod_ht40_chan_info HT40 Ch. 11 [2.4GHz]
WIDE (0x61 0dBm): Ad-Hoc not supported

And after the fix:
[91132.688706] ieee80211 phy14: U iwl_mod_ht40_chan_info HT40 Ch. 7 [2.4GHz]
IBSS ACTIVE WIDE (0x6f 0dBm): Ad-Hoc supported
[91132.688709] ieee80211 phy14: U iwl_mod_ht40_chan_info HT40 Ch. 11 [2.4GHz]
IBSS ACTIVE WIDE (0x6f 0dBm): Ad-Hoc supported

Signed-off-by: Shanyu Zhao <shanyu.zhao@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

When an internal scan is started, nothing protects the
is_internal_short_scan variable which can cause crashes,
cf. https://bugzilla.kernel.org/show_bug.cgi?id=15667.
Fix this by making the short scan request use the mutex
for locking, which requires making the request go to a
work struct so that it can sleep.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>