DS1WM: decouple host IRQ and INTR active state settings

The DS1WM driver incorrectly infers the IAS bit (1-wire interrupt active
high) from IRQ settings.  There are devices that have IAS=0 but still need
the IRQ to trigger on a rising edge.  With this patch, machines with DS1WM
that need IAS=1 have to set .active_high=1 in the ds1wm_platform_data.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Acked-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Acked-by: Matt Reimer <mreimer@vpop.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>