media: i2c: og01a1b: Add management of optional reset GPIO

Omnivision OG01A1B camera sensor may have a connected active low GPIO
to XSHUTDOWN pad, and if so, include it into sensor power up sequence.

Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>