Bluetooth: btusb: fix Realtek suspend/resume

Realtek btusb devices don't currently work after suspend/resume because
the updated firmware is quietly lost - the USB hub doesn't notice any
status change upon resume, but some kind of reset has definitely
happened as the LMP subversion has reverted to its original value.

Set the reset_resume flag to trigger probe and upload the new firmware
again.

Like the vendor code, I assume this is not needed when the device is
selected as a wakeup source and hence will retain power during suspend.
On the 2 products I have to hand, when trying this configuration the
hardware seems unable to keep the device powered up during suspend.
The USB hub then detects a status change on resume and does a reset,
so we do not end up in broken state.

Signed-off-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>