w1: complete the 1-wire (w1) ds1wm driver search algorithm

This adds multi-slave support of the w1 bus for the ds1wm Synthesizable
1-Wire Bus Master.  Also many fixes and tweaks based on the rev3 of the
datasheet http://datasheets.maxim-ic.com/en/ds/DS1WM.pdf

Signed-off-by: Jean-François Dagenais <dagenaisj@sonatest.com>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
Cc: Matt Reimer <mreimer@vpop.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>