[media] V4L: ov9740: Fixed some settings

Based on vendor feedback, should issue a software reset at start of day.

Also, OV9740_ANALOG_CTRL15 needs to be changed so the sensor does not begin
streaming until it is ready (otherwise, results in a nonsense frame for the
initial frame).

Added a comment on using discontinuous clock.

Finally, OV9740_ISP_CTRL19 needs to be changed to really use YUYV ordering
(the previous value was for VYUY).

Signed-off-by: Andrew Chew <achew@nvidia.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>