hwmon: (ina3221) Fix read timeout issue

After introducing "samples" to the calculation of wait time, the
driver might timeout at the regmap_field_read_poll_timeout call,
because the wait time could be longer than the 100000 usec limit
due to a large "samples" number.

So this patch sets the timeout limit to 2 times of the wait time
in order to fix this issue.

Fixes: 5c090abf945b ("hwmon: (ina3221) Add averaging mode support")
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/20191022005922.30239-1-nicoleotsuka@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>