iio: health: max30100: use msleep() for long uncritical delays

ulseep_range() uses hrtimers and provides no advantage over msleep()
for larger delays. Fix up the 35ms delays here to use msleep() and
reduce the load on the hrtimer subsystem.

Fixes: commit 4d33615d ("iio: light: add MAX30100 oximeter driver support")
Link: http://lkml.org/lkml/2017/1/11/377


Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Reviewed-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>