tipc: fix test of bearer_priority range in tipc_register_media()

For the bearer_priority to be less than TIPC_MIN_LINK_PRI and greater than
TIPC_MAX_LINK_PRI is logically impossible.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>