w1: remove unused and confusing variable.

Remvoe variable which actually is not used (except assigning it a value)
and confusing break out of the family checking loop.  Found by Harry Mason.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Harry J Mason <hjm03r@ecs.soton.ac.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>