Bluetooth: btusb: drop BROKEN_EXT_SCAN quirk for 0bda:a728

Commit 5ead2063611a ("Bluetooth: btrtl: fix RTL8761B/BU broken LE
extended scan") set HCI_QUIRK_BROKEN_EXT_SCAN on every RTL8761B, and
commit ca0583c24661 ("Bluetooth: btusb: limit RTL8761B BROKEN_EXT_SCAN
quirk to 0bda:a728") kept it on 0bda:a728 on the assumption that the
USB id separates dongles with broken extended scan from those with a
broken legacy scan path. It does not. An 0bda:a728 unit (RTL8761BUV,
fw 0xdfc6d922) on 6.18.51 fails the same way the UB500 and 0bda:8771
did: LE Set Scan Enable (0x200c) times out with -110 and btusb resets
the device. With the flag removed from the table entry, scanning works
on that unit.

Two dongles with the same USB id need opposite settings, so the device
table cannot key the quirk either. The costs are not symmetric. Without
the quirk, the unit it was written for gets -EBUSY on LE Set Extended
Scan Enable (0x2042) while a connection is up. With it, 0x200c times
out and btusb resets the device on three reported units, two of them in
a re-enumeration loop.

Remove the flag and the table entry. 0bda:a728 matches the generic
Realtek entry again and runs without the quirk, as before v7.2.

Reported-by: Andy Tsvetinskiy <andrew.tsvetinskiy@gmail.com>
Closes: https://lore.kernel.org/all/CAE4bxw+ofDFVx0aTHqCrzns9oP1CRQDm_wzeyHPeMBYOhSpcuA@mail.gmail.com/
Fixes: 5ead2063611a ("Bluetooth: btrtl: fix RTL8761B/BU broken LE extended scan")
Fixes: ca0583c24661 ("Bluetooth: btusb: limit RTL8761B BROKEN_EXT_SCAN quirk to 0bda:a728")
Cc: stable@vger.kernel.org
Signed-off-by: Junjie Cao <junjie.cao@intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>