batman-adv: convert bat_priv->tt_crc from atomic_t to uint16_t

In the code we neever need to atomically check and set the bat_priv->tt_crc
field value. It is simply set and read once in different pieces of the code.
Therefore this field can be safely be converted from atomic_t to uint16_t.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>

diff --cc net/batman-adv/bat_iv_ogm.c
Simple merge

diff --cc net/batman-adv/send.c
Simple merge

diff --cc net/batman-adv/types.h
Simple merge