drivers/rtc/rtc-ab8500.c: change msleep() to usleep_range()
The resolution of msleep is related to HZ, so with HZ set to 100 any
msleep of less than 10ms will become ~10ms. This is not what we want.
Use the hrtimer-based usleep_range() and allow for some slack in the
non-critical path so we have more control of what is happening here.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Cc: Jonas Aaberg <jonas.aberg@stericsson.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>