Refactored blocking operation of RTT backend. Log_output buffer
is used directly in case of blocking operation. Detection of
host presence added. Prevent use of RTT lock when in panic mode.
Removed pending on data being read by the host on every message.
Refactor gives savings of 300 bytes in ROM and 120 bytes in RAM.
Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
1cc9e98ae6