hwmon: (sht3x) wait predefined limits loading complete before access

An sht3x sensor include limits register which contains temperature
and humidity limit values. After a reset, pre-defined values are loaded
into that register. During the probe function, the driver reads the
limits register. However, if the reads are made too early, and the bus
is clocked at high frequencies (e.g. 100 kHz or more), the loading could be
not completed and the sensor returns a NACK which causes the probe to fail.
A delay of at least 500 us before the first read solves this issue.

Signed-off-by: Emiliano Ingrassia <ingrassia@epigenesys.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>