Bluetooth: Make hidp_get_raw_report abort if the session is terminating

After linux 3.2 the hid_destroy_device call in hidp_session
cleaning up invokes a hook to the power_supply code which
in turn tries to read the battery capacity. This read will
trigger a call to hidp_get_raw_report which is bound to fail
because the device is being taken away - so rather than
wait for the 5 second timeout failure this changes enables
it to fail straight away.

Signed-off-by: Karl Relton <karllinuxtest.relton@ntlworld.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>