media: adv7180: Only print 'chip found' message on successful probe

Currently the "chip found" message is shown even in the case where the
I2C address is wrongly passed in the device tree, or also in the case of
probe failure, which is misleading.

To avoid such problem, move this message after real I2C transactions
have been successfully made and we are certain that the adv7180 is
really present and probed.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>