fine parent clock of "camera" clock

The "camera" clock have only one parent. Define it statically and
remove unused source clock list.

Based on patch submitted by Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
(http://article.gmane.org/gmane.linux.kernel.samsung-soc/13691)

Signed-off-by: Andrey Gusakov <dron0gus@gmail.com>
Reviewed-by: Tomasz Figa <tomasz.figa@gmail.com>
Reviewed-by: Sylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>