media: i2c: ov5695: Fix power on and off sequences

From the measured hardware signal, OV5695 reset pin goes high for a
short period of time during boot-up. From the sensor specification, the
reset pin is active low and the DT binding defines the pin as active
low, which means that the values set by the driver are inverted and thus
the value requested in probe ends up high.

Fix it by changing probe to request the reset GPIO initialized to high,
which makes the initial state of the physical signal low.

In addition, DOVDD rising must occur before DVDD rising from spec., but
regulator_bulk_enable() API enables all the regulators asynchronously.
Use an explicit loops of regulator_enable() instead.

For power off sequence, it is required that DVDD falls first. Given the
bulk API does not give any guarantee about the order of regulators,
change the driver to use regulator_disable() instead.

The sensor also requires a delay between reset high and first I2C
transaction, which was assumed to be 8192 XVCLK cycles, but 1ms is
recommended by the vendor. Fix this as well.

Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>