msleep(1~20) may not do what the caller intends, and will often sleep
longer (~20 ms actual sleep for any value given in the 1~20ms range).  This
is not the desired behaviour for many cases like device resume time, device
suspend time, device enable time, retry logic, etc.  Thus, change msleep to
usleep_range for precise wakeups.
Signed-off-by: Aniroop Mathur <a.mathur@samsung.com>
Acked-by: Simon Budig <simon.budig@kernelconcepts.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>