net: decnet: Fixed multiple coding style issues

Made changes to coding style as suggested by checkpatch.pl
changes are of the type:
	open brace '{' following struct go on the same line
	do not use assignment in if condition

Signed-off-by: Sai Kalyaan Palla <saikalyaan63@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>