[media] exynos4-is: fimc-is-i2c: don't print error when adding adapter fails

The core will do this for us now.

Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>