In commit f44cb4b1 ("Bluetooth: btusb: Fix quirk for Atheros
1525/QCA6174") we tried to address the non-working Atheros BT devices
by changing the quirk from BTUSB_ATH3012 to BTUSB_QCA_ROME.  This made
such devices working while it turned out to break other existing chips
with the very same USB ID, hence it was reverted afterwards.

This is another attempt to tackle the issue.  The essential point to
use BTUSB_QCA_ROME is to apply the btusb_setup_qca() and do RAM-
patching.  And the previous attempt failed because btusb_setup_qca()
returns -ENODEV if the ROM version doesn't match with the expected
ones.  For some devices that have already the "correct" ROM versions,
we may just skip the setup procedure and continue the rest.

So, the first fix we'll need is to add a check of the ROM version in
the function to skip the setup if the ROM version looks already sane,
so that it can be applied for all ath devices.

However, the world is a bit more complex than that simple solution.
Since BTUSB_ATH3012 quirk checks the bcdDevice and bails out when it's
0x0001 at the beginning of probing, so the device probe always aborts
here.

In this patch, we add another check of ROM version again, and if the
device needs patching, the probe continues.  For that, a slight
refactoring of btusb_qca_send_vendor_req() was required so that the
probe function can pass usb_device pointer directly before allocating
hci_dev stuff.

Fixes: commit f44cb4b1 ("Bluetooth: btusb: Fix quirk for Atheros 1525/QCA6174")
Bugzilla: http://bugzilla.opensuse.org/show_bug.cgi?id=1082504Tested-by: Ivan Levshin <ivan.levshin@microfocus.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>