CDC NCM: release interfaces fix in unbind()

Changes:
- claim slave/data interface during bind() and release
 interfaces in unbind() unconditionally
- in case of error during bind(), release claimed data
 interface in the same function
- remove obsolited "*_claimed" entries from driver context

Signed-off-by: Alexey Orishko <alexey.orishko@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>