net: context: Release lock before passing RX data to socket

Release the context lock before passing data to the application
socket as that might cause deadlock if the application is run
before the RX thread and it starts to send data and if the RX
thread is never able to run (because of priorities etc).

Fixes #29347

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>