media: exynos4-is: Add support for multiple sensors on one port

On some devices, there may be multiple camera sensors attached
to the same port.  Make sure we probe all of them, not just the
first one.

Signed-off-by: Jonathan Bakker <xc-racer2@live.ca>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>