media: ov8865: Disable only enabled regulators on error path

If powering on the sensor failed, the entire power-off sequence was run
independently of how far the power-on sequence proceeded before the error.
This lead to disabling regulators and/or clock that was not enabled.

Fix this by disabling only clocks and regulators that were enabled
previously.

Fixes: 11c0d8fd ("media: i2c: Add support for the OV8865 image sensor")
Cc: stable@vger.kernel.org
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>