media: i2c: ov5640: Enable data pins on poweron for DVP mode

During testing this sensor on iW-RainboW-G21D-Qseven platform in 8-bit DVP
mode with rcar-vin bridge noticed the capture worked fine for the first run
(with yavta), but for subsequent runs the bridge driver waited for the
frame to be captured. Debugging further noticed the data lines were
enabled/disabled in stream on/off callback and dumping the register
contents 0x3017/0x3018 in ov5640_set_stream_dvp() reported the correct
values, but yet frame capturing failed.

To get around this issue data lines are enabled in s_power callback.
(Also the sensor remains in power down mode if not streaming so power
consumption shouldn't be affected)

Fixes: f22996db ("media: ov5640: add support of DVP parallel interface")
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Tested-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>