media: i2c: og01a1b: Add support of xvclk supply clock in power management

The OmniVision OG01A1B camera sensor has an xvclk supply clock, which
could be described and then explicitly controlled on OF platforms.

Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
[Sakari Ailus: Use UL specifier for power-up delay cycle value.]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>