media: ov2680: Fix regulators being left enabled on ov2680_power_on() errors

When the ov2680_power_on() "sensor soft reset failed" path is hit during
probe() the WARN() about putting an enabled regulator at
drivers/regulator/core.c:2398 triggers 3 times (once for each regulator),
filling dmesg with backtraces.

Fix this by properly disabling the regulators on ov2680_power_on() errors.

Fixes: 3ee47cad ("media: ov2680: Add Omnivision OV2680 sensor driver")
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>